Comodo is a little bugged, Qihoo IS is not really developed / supported anymore, Avast free ... I don't know I didn't use it in the last 100 years (since was version 4, I guess).
YOU will make the chart watching their reviews.
If you interesting in comparison of specific AV's send me a private message, and i will try to help you .
Thank you
2) if your are not logged into an admin account you wont get protection (they know the issue, they said there would be a fix sooner, i am still waiting for it).
well, in my pc some times the proactive defense overloads the CPU (some times means, to open folders in usb drives which has a lot of items)
Another thing is that if you use opera or chrome at least in IS version you wont get protection for bad urls. For TS also, but i have seen they added an url filter for chrome, i am not sure if it really works but as a opera user i dont see protection from both.