Thanks to Scoox to let me know this website, I'm one of the designer for DUMANG modular keyboard, and glad to answer questions here.
Hi Kent. I did pick up one of these on my China trip, and as I imagined, it's freaking awesome! My only question is, do you intend to make the configuaration software work on anything other than windows? I don't even have a windows machine so am unable to use it 
I‘ve refrained from buying new toys for a bit just so I can get stuff done, now thinking about getting one of these. Would love to hear more from you.
Oh hey there. So I've had this for months now, but honestly haven't used it loads, for a couple of reasons:
- It is not particularly portable, as it's heavy. That's good, as the aluminium base is SOLID, but if you have two of these, you'd have to carry both with you, so that's TWO mini plastic cases you'd be carrying around, totalling 3kg I'm guessing. Even in keyboard-freakery land, toting two keyboards looks really odd.
- Second, I can't use the software configurator as it's Windows only. Reading back on my previous post, what I wrote seems a bit misleading. I _can_ use this on my computer, but I can't use the configurator to do anything fancy, like one shot keys. All keys are 'as is'. Can still have fun trying out different layouts, but nothing high level, not until I can get hold of a windows machine anyway.
- It needs two USB ports, and I only have two on my machine, and generally one is occupied. A cable between the two would be a better solution maybe? Bluetooth would make me lose my mind.
- Finally, and maybe most importantly, I'm not sure if this is a daily drive type of keyboard. If you have a madcap idea for a new layout and want to try it out, this is perfect. No soldering iron, no wires even, not even hot swap sockets. Just push things around and you got your new layout. It really is a bit of a marvel.
Some random notes:
- Like I said, this is a hefty chunk(s) of metal. The base is aluminium and the key blocks themselves are solid units.
- Each block is held in place by fairly strong magnets, and under each block is a layer of tacky rubber to add extra friction.
- The ones I got, with the rectangular base (not the ergodox-shaped ones) are just over 10u by 7u. Doesn't mean you can fit 70 keys on a panel, I think max is 48.
- The keycaps that come with it aren't amazing. They have a 'gamer' font on them and are very sharp-edged. My thumbs weep. It appears to be a standard TKL set. Keycaps appear to be doubleshot, FWIW. White caps, clear legends.
- Another reason this keycap set is odd is that they're scuplted. Now, if you expect people to move keys around a lot between rows, I would have thought a uniform profile set would have been the choice.
- Swap the switches out to your heart's content. I got mine with Kailh whites, if I recall correctly there were several other options. But it doesn't matter does it anyway, cos er, swappable!
- I also bought a set of teeny-tiny ballbearings from the vendor, which you can stick in the shaft of Kailh switches to reduce travel. Though I was rather sternly informed that they WILL NOT WORK with white switches.
- The legs on each base board are curious mechanisms, plastic tubular legs that you can rotate in increments to set different heights. A clever method to be fair. I think the material could be nicer though, feels like they might break if I dropped this heavy baseboard from any kind of height with a leg extended.
- Set legs at different heights to get an asymmetric tilt. Flip the board 180 to get a downward tent.
- Unfortunately, they can't be removed, and there are two legs, both at front side of board. If, like me, you prefer your keyboard to lay completely flat, you're out of luck.
Overall, I'm delighted with my purchase, a very happy addition to the collection. I'll be sure to drag it out whenever I want to rapidly prototype a layout idea. If you have any questions, lay them on!
