There is a 2.3 release which seems to be much better in all respects. I do not know why it has not appeared in this area yet but the thread
contains 2.3 kext, toolkit and SDK, together with very clear info on which bits to use whether you have 285/4800 or something else. It also seems to compile a lot faster and subjectively I though performance was very slightly better. It does seem to banish many of the problems Mac people might have installing and getting going.
There is still the power management issue (e.g. deviceQuery shows a 285 shader at 0.6GHz, but this might depend on Apple revisions - I am using 10.5.7 - has anybody tried 10.5.8 ?).
No doubt I will be cursed by somebody finding something that no longer works, but so far it is uniformly better, even before you go to detailed enhancements.