Have you used the Realforce 87U keyboards? I find it much smoother and quieter, and the TKL layout and more weighting options seem to make it a better option for many.
I notice that board sounds nice and uniform. On my quite new HHKB, the center-most keys are much louder (the G,H, T, etc) and make quite a clack on the upstroke.
I'd love to try that other keyboard you have. I have never seen one here in Canada but I have a Keytronics board that feels and even sounds much like a 40g Topre switch for the most part and they are common enough and old. They aren't all equal, though, so getting a good one can be difficult.
I haven't used any other Topre board no, but I'd much prefer a proper fullsize like the 104. These space-saving layouts are a fun novelty for me, but certainly limit me while writing and gaming .
Forget Key Tronics, by the way . I find them constantly, but I've found them very disappointing considering the reputation people give them, and they're certainly no match for these BTC boards OR Topre as far as I'm concerned. I'd be greatly surprised if you can't find a BTC, by the way. They're among the most common non-standard dome boards I find (after NMB dome with slider ones).
Limit you while writing and gaming? I use a numpad a lot but only for spreadsheets. For gaming, mouse space is always key and my left hand only uses so much of the keyboard.
I've never seen one of those BTC boards but they don't seem to be all that cheap on eBay and who knows which ones are any good.
Keytronics keyboards vary greatly. I came across one the other day that was a contester for worst keyboard I've ever tried. However, like I say, I have one that feels quite similar to a lightweight Topre (40g or so). It has a hard bottom-out unusual for membrane keyboards and the rebound is hard as well. This makes it sound and feel similar to Topre with a different (not as nice) cup.
It doesn't help that here, recycling centers and such never sell their keyboards... they take them in and have they're gone. I can understand why, but it's unfortunate that I'm sure many a good things are gone to waste.
Don't buy a BTC off eBay. I find at least one every week so I'm sure you can find them in many offices.
I use the numpad for spreadsheets, but also for any other numerical input, and many of my hotkeys are set within the numpad.
As for what games are affected by a HHKB layout; surprisingly many. I don't play just one game, I rotate between a huge variety, so rebinding keys isn't always optimal, and surprisingly often not even possible. Some games that are affected:
-virtually everything made in the 80s and early 90s
-all games with ctrl in it, especially right ctrl
-all games with caps lock in it (a common bind for push-to-talk)
-all split-screen and similar multiplayer games (not enough room for both players)
-all games with hard-bound arrow keys in it such as Super Meat Boy and the Binding of Isaac, as well as many Flash games
-all games that use F and number keys such as Diablo 2 (skill buttons and potion buttons are the same)
-games that use the nav buttons, such as Syndicate Wars and Dungeon Keeper (no camera control) and some platformers (no view up/view down buttons)
Honestly it's surprising how many games are crippled by such a layout
.