My experience with Gravious (my Iyo) has been overwhelmingly positive. I can think of three problems that I have with it on an occasional basis:-
a) KinoAMP and
b) O2 both seem to be able to (vary occasionally) lock it up in a way that is not amenable to anything less than the hard-power switch at the back and even sometimes having to reboot it several times before it seems to recover. This has included a few times when it simply won't startup after such a hard-boot until after several minutes elapse. Very odd but thankfully rare.
c) a couple of times the display has awoken from sleep with a very strange timing (probably) error messing up things.
Oh and the graphics card fan has started sounding like a mercedes diesel.
As for problems with BASIC tokenisation - don't write BASIC.