FC660C is good, although most say that the HHKB s superior in sound, feel, portability, layout and so on. HHKB does have it's own unique layout, although it is possible to get used to it. I swap between HHKB at home and TKL at work regularly, and once you get past the initial \\\\ for backspace on the TKL, it's not much hassle at all.
Haha! I do appreciate the opinion on this, though it must have fallen on deaf ears because I am now the new owner of an FC660C-EW (pictures to come)
It's interesting that you bring up the backspace for the HHKB, because I actually enjoyed that so much that I've sort of missed it a bit. However, I just don't miss it enough to have the backslash and pipe up next to +/=
So far I'm really happy with the purchase, and I wanted to add a small note on the feel/sound comment you made: To me the HHKB felt a bit light, and without the addition of aftermarket rubber feet on the back it would slide around a bit while I typed on my desk at work. The FC660C doesn't have this issue as it is (just a bit) heavier, and has pads both on the bottom and on the feet - it feels to me very solid! As far as sound goes, I feel it's a bit more of a "thock" than the HHKB - which is more preference than anything really... I think they are both fine, just different.
I hope this wasn't too much of a rant... I'm very happy with my purchase, and still very happy to have joined in this community - I hope to have more conversations like this with you all in the future
)