Just my personal opinion, but AVG has been going downhill fast ever since version 7.5 quite some time ago. Starting with version 8, Grisoft started down the road of uncontrolled feature creep that was the downfall of Norton and McAfee before it.
Microsoft, to their credit, has managed to keep their hands off MSE. It's simple, it's light, it stays out of the way. For me, that is what I like to see. If you're looking for a program where the kitchen sink is probably in there somewhere, then AVG may be more to your liking.