I have no dog in this fight. I have Norton installed on one home machine and AVG on another. At work I have an enterprise version of MacAfee, version 7, I believe. My daughter has Trend. They all work.
I got Norton for my home computer because, at the time i got it, it was the only one that fully integrated with Outlook Express. It scanns incoming and outgoing mail.
Recently I upgraded it to version 2005. I was hesitant because CPU magazine had dongraded it for compatibility issues. I disabled the Norton firewall during installation because I use ZoneAlarm (Windows 2000, not XP).
I have no complaints about this installation, but I insatlled on a new XP machine for my boss and ran into firewall problems. It seemed to be blocking automatic updates for another program. This is never a problem with ZoneAlarm, because it always tells you what it is doing and offers alternatives in clear English.
I had Norton System Works on my Windows 98 SE notebook and they wouldn't let me renew it and forced me to buy Norton Anti-Virus 2005. I use "Add/Remove Programs" to uninstall it as directed and installed the new 2005 version.
It seemed to make everything run slower so I tried to de-frag but it hung up and said to run scan disk as I may have a problem with the hard disk. I had always used "Speed Disk" and "Disk Dr." in the 2001 version. Then when I re-booted I got a message that some of the Norton Anti-Virus files were missing, or not installed and that I must uninstall and reinstall Norton anti-virus which I dutifully did.
The slowness kept annoying me along with not being able to de-frag or run scan disk after defragging as it would stall out before finishing. I got the old 2001 version CD out and ran Disk Dr. from the CD and it fixed a couple errors and told me that the hard drive was 13% fragmented. There was no "Speed Disk" defragging program on the old CD so I tried De-frag again and that still wouldn't finish the job and screwed up Norton 2005 once again so I called their support line.
Today I went through FIVE technicians with East Indian Accents!!! (not that there's anything wrong with that) First I was told I had to download "Removal Tools" for both versions, old and new that they would email the links to me. Fine! Got the email but the links wouldn't work. Called 'em back and they promised to email the actual "*.exe" files to remove stuff left behind after the uninstalls so I could reinstall the new version without problems of defragging, etc.
Now the last one promised for the second time to send the danged email with the files I need to do this. When I called to complain they weren't coming, the techie led me through another effort at reinstalling just the new version and I let her get off the line just a little too fast when it looked like it was going to succeed, because it didn't!!!