I purchased a Truly Ergonomic keyboard based in no small part on comments and reviews here on geekhack. (Thanks, guys!) I spend a large chunk of my day on the PC either writing, coding, or gaming. I've had some mild RSI issues over the years, and I've mainly been using the MS Natural line of keyboards in its various incarnations over the past two decades.
I ordered the 109 key TECK on January 23rd. After almost two weeks of silence, it finally shipped last Friday and arrived yesterday afternoon (February 8th). And my account on their website still lists my order as "Pending". Their communication needs work. Seriously.
So I've had about a day to play with it now. Plenty of writing. Heck, I'm typing this post on it right now! I also played a bunch of StarCraft 2 to experiment with new hotkey setups that might take advantage of all the new keys at my fingertips. (Split keyboard configurations really starve you for keys in RTS games, and SC2 is easily the most keyboard APM intensive game in my library.) Obviously, that isn't enough time to fully evaluate the keyboard, but it has allowed me to shape some initial impressions, many of which echo what others here have posted.
Build quality feels very solid. It's surprisingly hefty for such a small keyboard. I love the compactness, as it allows me to place my mouse in a more comfortable position next to it on the keyboard tray.
The wrist rest is solid and pretty comfy. I haven't tried removing it yet (and frankly don't see why I'd want to...).
Cherry Browns are utterly delightful to type on. Why do I even tolerate non-mechanical switches? The market needs more selection in mechanical ergo keyoards...
The curved matrix layout is quite comfortable to use overall, and I'm pleasantly surprised at how quickly I've taken to it. The wrist rest and key shape/layout largely compensate for the flat design. (Coming off years of using angled boards that made me hate regular keyboards, that was a concern I was happy to find unjustified.)
My typing accuracy has admittedly taken a bit of a hit, but I mostly attribute that to the matrix layout punishing bad habits I've developed over the years. After a day of practice, I'm starting to get the hang of the layout, and my WPM should be back to normal once I unlearn some of the problem keypresses.
I'm rapidly coming to enjoy the new Backspace key. Given my reduced typing accuracy during this transition, it's seeing a lot of use. It's quite accessible as a finger key (though I found myself happily using it as a thumb key for the gaming tests). The Tab key is nice, too, although that's proving a little harder to get used to.
The new Shift key position will take some practice, but I don't dislike it at all. Given the curved distribution of the rows, it actually feels fairly natural. Accessing the bottom row does feel bit weird, but only the Z and quote marks are hard to modify. The Caps Lock key is honestly a waste of premium real estate on most keyboards, and the increased accessibility of the Ctrl keys is a big plus. One minor complaint: The key itself feels like it's shaped wrong. It's slightly raised and angled back relative to the adjacent letter keys, which makes it feel a bit high for my pinkies. The difference is especially noticeable with a gaming style Shift-WASD home position. I figure they may have been trying to lower the number of custom keycaps needed, but there's really no excuse for that at this price point.
I dislike the Alt keys. The shape and layout make reaching those corner keys unpleasant, especially as pinky based modifiers, and using them as such requires significant hand movement. Perhaps they should have swapped the positions of the Alt and directional keys. The latter are too unwieldy to use as thumb buttons without repositioning the whole hand anyway, and I suspect that many of us are already quite used to using Alt as a thumb key. In its current position, Alt-Tab is not a comfortable stretch. Neither is Alt-Shift, though I suspect that one might be slightly more workable with the oversized Alt on the 104/105. For people who use such key combinations on a regular basis, that's a fairly significant concern. (Disclaimer: I have kinda small hands. Your mileage may vary...)
Why oh why did they not slope the Enter key forward like the spacebars? Although I can definitely see myself getting used to a thumb based Enter, my thumb is hitting the hard edge of the key instead of the top, which is decidedly uncomfortable. I found myself occasionally swivelling to whack it with my right index finger instead.
At this price, I'd normally expect a USB hub.
The current lack of programming software makes it feel like an incomplete product, especially with the 109 keyboard having four buttons that don't do anything out of the box.
Remappings with which I'm currently experimenting...
Left Space to Enter. I'm liking this. Much more comfortable.
Enter to Alt. The central thumb button is an excellent place for a modifier accessible from both hands, although it still suffers from the shape/comfort issue mentioned above.
I'll probably be keeping the 2nd central key as Delete, but the desire to switch it back to its labelled quote function is growing. The regular '/" key is proving difficult to get used to, and it's not easy to modify with the right shift key.
I'm still not sure what I'll end up doing with the corner keys. Probably a few accented letters for easier typing in French. Depending on how I eventually feel about the new brace key positions, single keypress access to curled braces for coding is also a contender.
I might also move the / key back to the right side of the keyboard (either bottom corner or replacing the quote marks where it's supposed to be), since having it so far away from the brackets is annoying for using any kind of markup language.
Despite a few notable shortcomings and a company that desperately needs to get their act together, I'd rate my overall first impression of the keyboard as positive. Comfort and quality wise, it blows the MS Natural keyboards away. My experience with the higher end ergo keyboards is very limited, so I can't offer much comparison with its direct competitors like the Kinesis. Although it's certainly the most expensive keyboard I've purchased for a PC, I'm inclined to think it's reasonably good value for an ergonomic tool I'll be using every day. On the other hand, it's sufficiently different from other keyboards that I could foresee needing more than one to support multiple computers once I'm used to it, and that could get uncomfortably expensive rather quickly.