Actually almost all of those things are done by MSE but in a different way. The only things not in MSE are the IM shield and the mail shield. A lot of people will say that a mail shield in an AV is not needed anyway. If you also use Internet Explorer, MSE integrates with that to provide some very good browsing protection. MSE’s heuristics may also even be better than Avast!'s right now.

The reasons why I don’t use MSE are very slow scans, a perceived performance hit, and the fact that on the other machine here, MSE totally failed to upgrade both times program updates were offered. It got stuck during the process of urgrading and left the machine with no functioning AV protection until MSE was completely uninstalled manually and the new version redownloaded and installed. That was just not acceptable so that machine now also runs Avast! free.

I have never received an option to download MSE from Windows update. All I see is it listed as a category but when I click on that, there are no downloads offered.