I reported in a different thread what I think of Norton. I received several trojans that apparently were welcomed by Norton as they all turned my PC to mush. I installed Kaspersky yesterday and don't know how well it will work but it can't do worse than Norton (I hope). And yes I did automatic updates with Norton and scanned weekly but all to no avail.
Everyone has their preference, personally I've used Norton for about 4 years with no problems at all, but a virus did get through a couple of months ago. I decided to try AVG free and I'm happy with it although I've only been running it for about 3 weeks. One thing I have noticed is AVG updates are available almost daily but Norton ones were almost weekly. It just seems that AVG enable updates faster though that may just be the impression I have. Norton is meant to be a system hog but I never had a problem with it slowing up my PC. I can't say AVG is better than Norton its too soon, ask me in a year. Course the big advantage is AVG like AVAST is free.