People are talking about the DM Calculators, and they're saying great things:

Eddie's Math and Calculator Blog (February 23, 2018)
DM41L at work (Thanks Geoff, very impressive!) (2016) 'The rebirth of the HP-12C: How one man reimagined a calculator from 1981' (2015)
Bring Back The HP-15C (2015) (2015)
Retro Thing: Boutique Swiss Made Calculators (2014)
electrical measurements of the DM calculators (2013)
The Museum of HP Calculators (2013)
calculator review on (2013)
The Calculator Store (2012)
some spontaneous compliments and kudos
I haven't been this excited about a calculator since I first learned how to program on an HP 67 back in 1976.
It's been almost 20 years since HP put their name on a quality Advanced Scientific Programmable RPN Calculator
and nobody else has either until now. Despite being a small company, David and Michael have demonstrated their dedication to improving
quality until they've produced a product that's comparable to the best that HP ever made.
The DM 42 calculator is 450 times faster than the HP 42s, calculates with 34 digits, displays 10 lines of code, has 10 times as much
memory, has its own USB drive, and Programs and Matrices can be sent back and forth to a computer via a USB cable.
It looks and feels great, and in the weeks that I've had one, I've known it to be reliable and durable.
The convenience of Bill Hewlett's shirt pocket sized numerical tool can't be over stated:
It's just as important today to scientific professionals, students and teachers as it ever was, and I still believe it's the best way to learn how to program.
Jim Crepps, , USA, 2018 Mar. 3,

Thank you for creating the DM42. It is very high quality, feels great in the hand, and is superior to the HP-42S in every way.
I was initially a little concerned about paying $200 for this calculator, but now that I have it in hand it's clearly worth every cent.
Chris Hanson, Software Engineer, Google Mountain View CA, USA, 2018 Feb. 14,

The DM42 just arrived. It is awesome! The build quality is outstanding, and the display is the best I've seen on a calculator.
You may have outdone yourself, building better HP calculators than HP could.
John Sonewald, Knoxville Tennessee, USA, 2018 Feb. 13,

I am extremely satisfied with the looks and the build of the DM42.
It is another step up in quality and craftmanship compared with the DM15 and the DM41L that I acquired earlier.
The screen, the keyboard, the outlook and the heft of the calculator exude quality.
HP-like quality. Eighties-HP-like quality, to be more specific. This HP-42s reincarnation is a thing to behold in its own right.
The screen is vastly superior and of course the speed, the memory size and the numerical precision are also much better.
The connectivity that was notably missing on the HP-42s has now been restored.
You gave us a terrific physical incarnation of Thomas’ terrific simulator – and more.
Just to say that I am really grateful for this very nice piece of Swiss craftmanship.
Jeroen Van Nieuwenhove, Leuven, Belgium, 2018 Jan. 8,

You are to be highly congratulated on what you have achieved with your DM42 project.
The build quality exceeded what I was expecting.
My first calculator was a HP35 in 1975 and have had HP11C and HP42s calculators since for use in work.
Your DM42 will see me out till I retire and can be considered the best of all the calculators I had.
Frank Kosztelnik, Katoomba, Australia, 2018 Jan. 6,

I am overwhelmed by the quality feeling of the DM42 calculator, it's just awesome. I had high expectations but it turned out to be even better!
Very strange to put it side by side with my HP-42S and seeing the writing on the back. One says 1987, the other 2017. Wow, 30 years..
Hats off to you for your fantastic work with bringing back the HP-42S and even improving it in many ways.
Many, many thanks!
Frode Stokke, NORWAY, 2017 Dec. 19,

The DM41L arrived today, it is absolutely terrific.
And I want to give you, and your company, my most sincere compliments on making this superb calculator.
The HP-41 was a legend in its time, and many of us that went through college with one still regard it as one of the best calculators ever made.
To have it back again is quite the experience. And, the craftsmanship of your 41 is terrific.
Excellent keyboard feel! Just right on the tactile response. Excellent, high contrast LCD. Solid feeling construction throughout. A real gem!
Mark Puscas, Salem, Oregon USA, 2017 Oct. 12,

I have just received the DM15L calculator and am very happy with it. This is a superb bit of kit and a worthy successor to the legendary HP15C.
I'm well aware that your calculator is functionally far superior to the HP, but demonstrating excellent quality too is a nice surprise.
The cherry on top; brilliant service from you.
Stephen Wood, Welwyn Garden City, United Kingdom, 2017 Apr. 25,

I just had to write you about the quality of the DM 15L - it is amazing.
This is truly a work of ART!!! I love the voyager design, now I'm gonna have to order all the others too!!!
YOU really have skills, I truly admire your work in bringing these lost gems back to life with 'old hp way' quality.
Bill Hewlett and Dave Packard are not gone! They just moved to Switzerland!
Dan Wharton, Santa Cruz CA, USA, 2017 Mar. 30,

The DM41L is a perfect calculator simulating very well the original I also own.
The item i received had a small defect on the screen and Michael implemented a very quick action to get everything fixed.
It has been for me the occasion to see that the internal conception and making of the calculator is at a very high level of quality.
I recommend these calculators, the ratio price / quality is very good.
Olivier M.Nantes, France, 2016 Sep. 17,

I am really impressed by the quality of the calculator which is a result of your big commitment to these products.
The extended memory, the USB port and the reduction of power consumption are clear benefits over the HP products. In particular, I can finally write and store long programs without fearing that they would vanish every few weeks due to randomly occuring 'Pr Error' conditions. The low-battery indicator of the HP-15C LE doesn't work!
The keyboard is also much better than the one of the HP-15C LE and even better than that of my original HP-15C.
Pascal L., Vienna, Austria, 2016 Apr. 23,

Thank you for sending the DM15L which is working well. It is a brilliant design. It should end up in a design museum.
In combination with the Simulator from Torsten Manz it is a practical everyday device.
John Patterson, Wellington, New Zealand, 2016 Jan. 21,

These miniaturized wonders are so nostalgic of the original HP's. They operate flawlessly, are actually upgraded
from the originals in both firmware, hardware, and in quality. These calculators feel great in your hands and have a good weight to them.
These are serious replacements for the originals. If you are still nursing along your old favorite HP,
its now the time to retire it and switch to the new modern, soon to be classic, SwissMicros DM series.
SwissMicros really knows how to take great care of their customers too.
Gregg Bergman, Southern California, USA, 2016 Jan. 03,

I have just received the DM16L (serial #135) which I ordered from you last week. I just want to say I am very very impressed.
It actually feels more solid than my (two!) original HP 16C calculators.
Although I like your original credit-card sized calculators, this full-size one is in a different league.
Very well done, and thank you so much for keeping these wonderful calculators alive, relevant, and hackable.
S.J.London, United Kingdom, 2015 Dec. 11,

Just wanted to let you know I received the DM15 today and I'm really impressed.
You have done an excellent job creating a faithful recreation of a classic piece of technology,
while putting your own signature on the device that makes it unique and classic all at the same time.
The quality and care you took in building this is evident. Well done!
Jason D., Pennsylvania USA, USA, 2015 Oct. 31,

Congratulations; a very nice work.
You have done a great thing in building the HP15 at a size that leaves no doubt about what progress means.
The equivalent in space technology would be a private company sending people to space although the start was done by NASA.
Prof.I.Purica, Bucharest, Romania, 2014 Oct. 16,

Many thanks for the DM15, which arrived yesterday. Fantastic Service! It arrived quicker than most post from London. Much appreciated.
You guys are wonderful and the DM15 is outstanding. An answer to a prayer! I shouldn't say this, but you should charge more. You are seriously under-pricing these.
Prof.Tim Spracklen, Huntly Aberdeenshire, United Kingdom, 2013 March 06,

This appears to be the coolest electronic device I have seen for a while.
Thank you for creating this device and making it available to everyone.
Gregory W. Litteral, Indianapolis, USA, 2013 April 05,

Ich habe gestern noch mit dem kleinen gespielt. Das Ding ist wertiger als man das auf eurer Homepage vermuten mag.
Bin damit sehr zufrieden. Die Umsetzung ist euch echt gelungen. Habt ihr super gemacht!
Rene, Ebersberg, Germany, 2013 Dec. 12,

The calculator is really great. I wish I had found out about these earlier.
Thanks very much.
John Sonewald, Knoxville Tennessee, USA, 2013 July 13,

Your DM15 arrived today and it's PERFECT !
Great engineering and software work, thank you very much.
Alessandro Bruciamonti, Pavia, Italy, 2013 Sept. 25,

Das Gerät ist einfach phantastisch, das perfekte Spielzeug und Geschenk für den Nerd.
Dipl.-Ing. Manfred Pecha, Wien, Österreich, 2014 June 26,

The calculator arrived today. Both it and the case are prime examples of expert craftsmanship. I applaud you and your folks.
I will have many fun calculating hours. Thanks, again.
John Cadick, Garland Texas, USA, 2014 Feb. 24,

The calculators have just arrived. Thank you! They're great, and the size is just perfect.
I have the original HP15C and 16C, but they're not as pocketable (or customisable) as yours. The raw titanium casing is a nice touch!
S.J., London, United Kingdom, 2014 Oct. 19,

I have today received a DM15CC. My reaction? Frankly awesome.
Can it be improved? Not by much.
Is the size an advantage? Surprisingly yes.
Would I buy additional ones? Actually yes I would - because the DM15CC would be a carry anywhere tool.
Is the price a problem? Not really. If a more expensive say DM42s came out I'd still consider it.
Nigel W., United Kingdom, 2012 Nov. 22,

My package has arrived yesterday, and the product is fantastic!
Keep up the spirit and good work, I am your fan from now and will show it to others and promote.
Peter Princz, Tahitotfalu, Hungary, 2014 Feb. 25,

A quick word to say thanks for an excellent product and excellent service.
The DM15 works beautifully and I was very pleased when it arrived only 72 hours after ordering.
Alles ganz erstklassig!
Roger Stokes, Caistor Lincolnshire , United Kingdom, 2013 Sept. 02,

I saw your site while doing a Google search for HP calculator emulators, and was blown away with the work you have done.
I wanted to drop you both a message of thanks and compliments on the excellent work you've done on these models.
I see these examples as artwork as much as working examples of HP calculators, and I salute you.
Thank you for your interest and detail in these beautiful pieces of technology.
Shawn Tinker, Cincinnati Ohio, USA, 2014 Jan. 15,

A big huge thank you to all you guys who have brought the DM1x series to the market!
A less expensive, pocket-sized, and (most importantly) currently produced version of every RPN enthusiast's favorite calculator... yes please!
Ryan McKay, Davis California, USA, 2013 Aug. 06,

... I recall seeing some notes regarding improvements to the calculators, and from a quick test of the new ones I am actually even more impressed than before.
Very nice products! And the flip-open pouches in particular are a superb addition, forming what could be a sort of mini-system. My compliments.
D.G., North York, Canada, 2014 Dec. 06,

Just wanted to drop you a quick note to say that I think your product(s) are absolutely fantastic.
I received my calculators a few weeks ago and I am speechless with admiration! Many congratulations on your achievement.
I continue to amaze friends and colleagues when I take this calculator out of my pocket.
Oliver Williams, London, United Kingdom, 2012 Nov. 12,