SpyBot is not as effective as Norton's. Also, last time I checked, SpyBot will not continually monitor your system like Norton's. SpyBot is designed primarily for tracking cookies and Norton's for malicious viri.
Spybot does have a feature to watch you browser... Does not protect your entire system like Norton. I have had nothing but issues with Norton since 2004 so I don't use it. This has never failed me, and uses less sys memory. http://www.kaspersky.com/
SpyBot is not as effective as Norton's. Also, last time I checked, SpyBot will not continually monitor your system like Norton's. SpyBot is designed primarily for tracking cookies and Norton's for malicious viri.