Norton and McAffee are the AOL of PC Protection. They burn through RAM fast enough that only 256 megs of RAM will up your PC's load time by well over a minute. I've seen it happen. A / B comparison, I'd format a machine with 256 megs of ram, fresh install of XP, fresh install of Norton, bang, lose a minute of startup time. =\
Oh, they don't do a good job of finding virii either. I would scan things in Norton (My boss LOVED Limewire), transfer then to the minidrive (6g laptop hd converted to USB drive) and transfer whatever it was to my PC (The network fileserver), sure enough my copy of Avira would go off with a virus alert. When Norton DID find a virus, 90% of the time it'd try to delete, then quarantee the virus and fail both times.
Oh, and their update process is STUPID. STUPID STUPID STUPID. Takes too much time, too much bandwidth, and need to restart a half dozen times just so you can update crap Norton can't even use properly.
Their interface is just stupid. In Avira, I right click the bottom icon, click update, it downloads the updates, stops the antivirus, installs the updates, restarts the antivirus all on it's own. In Norton, sometimes it would fail to update at all, I'd have to download the manual updates, and run some lame-*** update installer to get it to work. Too much hassle.
You want a real antivirus? Try Avira, Bit Defender, or Etrust, all of which are pretty good antiviruses.