Personally, I hope that Ctrl won't be sticky (or this should be configurable); with two hands, it should be OK, in particular because the device is smaller. But I haven't tried...

Concerning the xterm keys, I find this feature very useful, though very limited (reduced number of keys). I'd like something similar available for any application and entirely configurable.

BTW, how about the special characters used in some languages, such as French (e.g. éèêë âîôû àùïç)? With the N810, I can enter them without using anything on the screen, e.g. with Chr+eee for ë (this is very useful). Unfortunately, as the N900 keyboard has fewer keys, in particular no Chr, something like that doesn't seem to be possible, perhaps except with special key combinations. I wonder if something like pressing two keys at the same time could be used to enter additional characters. Otherwise I hope that the on-screen additional key feature is configurable enough (on the N810 it is rather useless). I also sometimes need other Unicode characters such as the mathematical ones.

Note that even though I often write in French, I also program a lot, so that I want to stay with a traditional QWERTY keyboard, not a French one (and in particular I want the 4 distinct arrow keys).