Not really qualified to reply - as I don't use 3.5x for anything other than testing website compatibility (I do not approve how they f***ed up the color profile support in it), but 3.1.something has worked very well for me.
Yes, I can make it crash. After it has been on for two or three full days, with 70+ tabs. I don't really blame it in that particular situation. In any case, by that time it's using 1+ GB of memory, probably mostly for the histories of all those tabs. It obviously does have a memory leak, but not bad enough to really bother me.
Chrome, Iron and Opera are all good browsers, but the severe lack of plugins is a buzzkill for me.
EDIT: Safari 4 is also very capable browser - the rendering engine is the same as in Chrome and Iron (might be bit more recent version, dunno), but it too has a acute lack of extensions, and of course the entire logic of the GUI is very Apple-like, which can be somewhat of a pain, when you use it in Windoze-environment.