Spotlight is, generally, only slow the first time you search.
Usually it's as fast as LaunchBar except for the very first time it is used. It has a reputation of being slow from 10.4 that is no longer justified.
I've found that it is consistently a few seconds slower. It's not slow as such, just slower than QuickSilver. And when it come to app launching, these few seconds kill, imho.
How do you disable spotlight indexing?
Also, I haven't had any problems with crashes or anything like that... works great here.