The update is very comprehensive and will work on ARM 710 machines all the way through to the Iyonix (OK slower hardware probably will work as well, but its not worth mentioning). I'm not aware of any remaining bugs in the game and its generally faster even on old hardware. The sound system is much improved ande provides better atmosphere - and it will use the higher sample rate samples (in Descent 2) if the are installed. Basically everything is better. If you upgrade and you *still* have a problem (unlikely) then pass info along to RCI and I will sort it out - unfortunately I can't provide such support for the old version any more as so much has changed.
Upgrade you know you want to