memadmax
AVG is NOT better.
In fact, it's a bloated resource hog, and it's detection ratio was not something I found remarkable (they apparently improved it lately, but it's still one bloated piece of software).
As for MSE... I've been using it since version 1.
And I can't say I had issues with it at all.
I never experienced system hangups during definition updates or scanning (true, the full scan when done for the first time ever is a bit slow to do, but doesn't really kill my laptop when doing other tasks).
All in all, I found MSE to be quite good.
Avast may be a tad lighter and have slightly higher detection threshold along with Avira, but the latter can be attributed to a high number of false positives (which is the lowest on MSE), and Avast did me a disservice few times when it found that all websites I visited were malware infected (a fault in definition updates - but it was enough to get me back to MSE which incidentally also doesn't need a yearly subscription renewal for the free version - some users who aren't computer literate to a high degree have a problem with this particular renewal).
I'm excited to see Microsoft claiming these updates to the software. If they turn out to be accurate, then they will only further improve on an already solid software.