How much does the bug spoil the game experience. Now I've only played KOTOR II on the Xbox but I never came across anything that I would say spoiled the game experience. On the other hand Bloodlines got slower and slower the longer I played it ,often crashed between transit points and in the end just shut down without warning. That was not only noticable, but also extremely annoying.
I did come across the Red Sun bug (the slaver event not triggering) on my second playthrough of KOTOR, although obviously if I was reviewing it, then it wouldnt have made any difference.