It seems every antivirus suite gets flack at some time or other. I have been influenced in the past by magazine reviews and personal recommendations on technical forums. First Norton was flavour of the month then it was labelled as bloatware. Try Panda said a forum member - lots of agreement. Then it was labelled as too intrusive. Later I switched to Kaspersky as it seemed to be scoring highly and I have to say I have been happy enough with it though all the background options make it very complicated for a non-technical PC users.
My main point being that every AV software pack has some issues, but if they don't cause too much trouble and do their job, why knock it? The only minor issue I've had with Kaspersky is a slight delay (maybe 10 seconds) in first opening a second tab in IE. After that initial tab, others open fast.