The big difference that you'd notice is an increase in speed, not huge, but an increase none the less. Norton likes to get it's paws on everything, and in most cases adds about 20-25% overhead onto your system, eating valuable resources. McAfee used to be a better choice, but now it's as bad as Norton. I've seen Norton's do some stupid things to computers, that's why i try to stay away from it when i can.
Some will argue against me, I've heard people say that they love it and wouldn't go with anything else. Personally, I'd sooner go with nothing, however with AVG Free Edition for Home use, it's a much better alternative.