I would not go for AVG from my (short, fortunately) experience with the free version of it...
I hope the paid version is way better than the free one 🙂
Personally, for Windows I would buy Avira as its free version worked great for me, so I can imagine the paid version. But now since I use Linux, I'm not really bothered with using an antivirus. Only installed ClamAV and I think it's enough (at least until more viruses for Linux appear).