After reading all this thread, i finally decide to give Bitdefender another shot, as i had it on windows 7 and it messed up my windows 7 drop shadows(still i used it for 1year!!), since i am on windows 8.1 thought it would be a good idea to give it a shot and damn installation is just horror movie!!
I have used some of the best antivirus and internet security, here is what i found:
Norton 360 = Easy to use and install, Really Fast, and top rated by AV-TEST (my sister's laptop use this, and my favourite).
Bitdefender Total Security 2015 = Installing this is a Nightmare, Super Fast, Looks badass, and this THE TOP-RATED AV-TEST product for years.
Kaspersky 2013 = It is good, but i had some issue with it's update, one of the bad update caused it to freeze whenever check for updates
McAfee = Probably the worst, i haven't found any plus point yet :|