Used to use AVG but it got over-bloated so switched to MSE. No problems, but then again it isn't until malware is missed and it starts messing up your system that you wish you used a different product. Mind you I suppose no products 100% effective all the time, so MSE might miss something that Avast picks up and vice-versa.
I think having regular back-ups going back a week or so at least is more important should something go wrong.
Last I heard MSE was about the worst of the heap. I used to recommend it all the time, my thinking was who would know how to protect Windows better than MS? Turns out it's some other company!
--------------------------------------------- Give me liberty or, I dunno, something.
I can't say I've had problems with it, but the people who test these types of things say it's pretty shit. I got the attached information from this site. The only thing MSE did well was not wrongly block files. I think that's because it lets pretty much anything execute! :) Anyway, I just wanted everyone to have this info, makes not to me what people use as long as I'm not the poor bastard that has to clean it up!
*Well wtf? I guess Matt's chosen a more stringent AV here at Teh! It won't even let me attach pictures! I shall remedy this shortly!
--------------------------------------------- Give me liberty or, I dunno, something.