The problem with the ads in the free-ad version is fixed again in 3.5 build 43534.. which is curious.. because it's the same build. The program didn't change, but the ads stopped popping up.
I love utorrent.. and the charge to get the ad-free version is well worth it (when it works)... however, that ad engine makes the "free" version essentially "crippleware". There is no reason why those ads should take up 57% of my cpu and 700 megs of memory. It should be less than 1% of cpu.. and at most 1 meg of memory.