I used both but I am not using neither one now. I prefer MSE over
Avast for no reason in particular. Avast never gave me any trouble
but for some reason I got bored of using it after 4 months. MSE 1
was perfect on my XP SP3 system but when version2 came out, I
started experiencing CPU surges too often, that's why I am not
using it now.
After MSE 2, I stopped using AV real time.
Bo