I hate to be the one crashing the party

, but F-Secure isn't that bad. in the on-demand test it's detection rate is 97.9%, when avast has 98.0%. in the retrospective test F-Secure scores 56% and avast 53%. all of this according to the latest test on av-comparatives.
I moved from avast 5 free to F-Secure Client Security 9 until avast 5 gets more polished. I have no problems whatsoever, everything running ok. the Internet Security versions 2006-2009. and also the Client Security versions 7 and 8 from f-secure were pretty heavy, that is why it has a reputation of resource hog. but the latest version, especially the Client Security, is way better. it's evolution is similar to that of Norton in this regard.