(In my opinion) the free tools are just as good, but as you say you don't get the support. If you are and experienced user support is not an issue, the free ones are fine (and often do just as well in reviews), but if you want the support then pay for it.All free antivirus software is IN MY OPINION generally not as good or as reliable over a long term as antivirus software which is paid for and has hourly updates and technical back-up if required.
IF that were the case, then nobody would buy it.
Spent last weekend working on two PCs for friends, one had the latest Norton and a bad case of Zlob, the other had Virgin PC Guard, Vundo and about 100 other bits of spyware. I did my usual sequence of killing a few processes in taskmanager, manual registry editing/deleting, re-boot, run the bitdefender and trend online scans. This normally does the trick, but in this case it didn't so I had to add the extra step of installing spybot and scanning with that - all sorted then.
So can I recomend Spybot to go along side AVG or AVast, it's on all of our PC's but set to manual mode and I've not needed to use it for so long I'd forgotten how good it is.