I have it running alongside Spy Guard (probably over kill),and I seldom get a hit on either one any more. However, when I first installed it, it found things that Spy-bot Search and Destroy didn't find. I also run Ad Aware and it finds things that the other two miss.
So from what I have experienced no one anti spy software has yet been able to catch everything.
I am hoping that as Microsoft further develops it's anti spyware that it will become the best as far as catching everything.
!#&$ <font color=blue> </font color=blue>---<font color=red><i><b>It's not heavy,...it's my computer</font color=red></i></b>