I use both. I have Spybot set up to run every time I startup, as it's faster than Adaware. I run Adaware about every three days or if I get a prob. It occasionally gets something that slips by Spybot. Recently, I had a problem ridding myself of "Whatzit" resetting my homepage when I used IE (which is rare). The most recent Adaware update caught the prob, but Spybot missed it. I really appreciate the additional tools, like the shredder in SB. Go for both to be safe. They're small downloads, and small programs, so what the hey?