I have been using MSE since 1-11-2011, I had used KIS before that time. I must say that MSE performs very well on W7. I gave up on KIS because of the system drain. I have found that MSE performs very well on W7. That said, it does not protect WXP very well. I like MSE on W7, but I would not use it on WXP, There are better solutions for WXP. So what are other user opinions of MSE?