I never trust the free anti-spyware (except Microsoft of course). I had Spybot but it is undependable. The trial versions of both CounterSpy & Spysweeper were finding things that Spybot didn't. Add to that, the fact that sometimes it seemed a whole month would go by before there was another update (Spy Subtract, a paid program was the same). It didn't give you much peace of mind,knowing that there is new spyware being created all of the times. With Spysweeper & CounterSpy, there are always updates. You feel more protected. Spysweeper has over 89,000 spyware signatures and I hear CounterSpy has even more. Ad Aware, was always even more useless than Spybot. It seemed to just find cookies. Add to that the fact that LavaSoft backed down from the scumbags from Hot Bar who were threatening LavaSoft with a law suit for detecting Hot Bar as spyware, and that LavaSoft changed their software so it no longer detects Hot Bar, makes it (at least in my eyes), useless and untrustworthy.