Thoughts on Spy Sweeper?

I'm looking at Webroot's Spy Sweeper program to fight spyware and
adware, since this month's PC World gave it their highest rating.
It sells for $29.95. It's interesting that PC World named Sunbelt
Software's Counter Spy their "best buy" a month ago, which is why
I bought it. Now they say it's not that great. Any opinions on Spy
Sweeper? Would it work to run both programs on the same computer?
I'm thinking that they both have a feature that runs in the
background.

Thanks!
Scott