Username or EmailPassword
On my systems at home and in the office. I have also been testing it on infected systems that come into the shop. (We are a small repair shop.) I like it so far, but I have run across the following issues:
It seems that you must run as administrator to receive program updates, at least on XP. I'm not sure about definition updates. This is a step backwards from other AV programs. I can't see why the service responsible for the updates can't run at a higher privilege level than the logged in user and perform the update.
I also have seen a few instances where MSMPENG.exe decides to take 100% of the CPU. This was only on a small minority of machines, mostly older boxes.
Other than these two issues, I absolutely love it.