I spotted this useful page to help you make your mind up as to what the most effective spyware remover is and got some surprising conclusions.
The test was to detect and remove spyware on a preloaded PC (Same test /same spyware varieties every time)
There are currently 6 pages of 3 tests 2 weeks between them (Quite recent last one),same loads,but I think with the current update for that timeframe. Hence the variations in the findings OK?
It's a wee bit gobbledegook but check out the detection numbers at the foot of the columns
http://spywarewarrior.com/asw-test-results-1.htm
And here is the explanation page if you can follow it?
http://spywarewarrior.com/asw-test-guide.htm
There is advice on lots of aspects of spyware here as well