A year ago I'd have just said an unqualified yes, but since SpySweeper 5.0
was released, I think it depends on what security items in total you have
running in real time. That includes what Anti-Virus products you are
running. The potential for conflict is high, as "someone" alludes to
above. I'm running a backlevel version of SS that's over a year old, not
wanting to inflict havoc on my system.
The good news is that you can try SS for 30 days free to see what happens.
Although be forewarned that removing SS may involve more than a simple
add/remove from control panel, and you may need to get Webroot support
involved to totally remove the product if that turns out to be necessary.
See these forums for more detail:
http://www.castlecops.com/f163-Spysweeper.html