I have been using the HHKB so much now, I having a hard time with regular keyboards. I can't tell you how many times I have typed \\\\\\ trying to press Backspace..
That's the issue with going to HHKB if you use multiple computers. It becomes a challenge to use a non-standard layout and go back and forth between that and other normal keyboards. (Which is why I've stuck to qwerty, but that's another discussion)
With the design above, you can easily go back and forth. It's basically a full featured standard layout like a Model M with some extra modifier keys... that has been compacted as tightly as possible without affecting layout.
The Realforce 87u is almost perfect to me. The 76u is basically chopping 2" off of the top of the 87u and merging Fkey functions into the number key row. Pretty simple and would be very effective. It's like the next evolutionary step after tenkeyless... it's Fkeyless but maintains a standard layout so there's no learning curve to using it.
The HHKB is an excellent design with it's merits for some niche users, but this keyboard is for anyone who wants a compact or portable option without being cramped.
I prefer the layout of the Japanese HHKB Pro 2 with it's arrow keys and extra modifiers but there is still the issue of the wonky enter key and needing to use a modifier key to backspace. Personally I think the HHKB lite is the best layout of the HHKB series. But the 76u layout for me is more functional than any of them due to the types of key combinations I use on a daily basis and that there is no layout adjustment or learning requirement to use it.
Realforce 76u - Standard US layout in a Compact Board
US/Standard HHKB Pro 2
Japanese HHKB Pro 2 w/Arrow Keys
HHKB Lite 2