The problem is that many of those regulars on the forums, will rarely have anything found by either program as they exercise a degree of common sense and practice safe hex.
However, you only have to view the viruses and worms forums, etc. to see just how effective they are over and above tracking cookies. That is with in most cases they had adaware (waste of space) and or S&D installed, not to mention avast. So they are most certainly complimentary to avast and better that the rest of the anti-spyware/malware applications IMHO, certainly that I'm aware of.