I don't often disagree with you Malke, but on this occasion.....
I have used AVG free (and the occasional paid-for) on Win 98,ME,XP,and
Vista - and even for a short time on Win 7- and have until lately
recommend it without reservation to my clients - NEVER have I had a
problem that could be traced back to AVG (although there was the
occasional time when it would not work, a simple uninstall/reinstall
fixed it).
Since V8.5 came out, I've noticed that there is a significant slowdown
on older PC's - usually with limited RAM (<512MB), running XP - this
has led to me evaluating Avast on Vista, which seems slightly better
than AVG, and has not given me problems so far.
I would agree/admit that AVG is not the 'best' AV in the world, but
for most of my (mostly clueless) clients, it's ideal, because of the
simplicity of the interface.
The only proviso is that you should NEVER install the email checker -
which is the part that does cause problems ( as it does in many other
AVs). At least this is simple to do, in the AVG install - unlike
certain other well-known AV's!
Avast, while it seems to be efficient, does tend to have a rather
complex interface (which I personally despise) - seeming to try to be
at the same time twee, and techie. It fails in both, but does actually
give a lot of options. If only its interface was as simple as AVG's, I
would wholeheartedly recommend its use to all my clients.