As I said in your other thread - both are great choices. Allow me to elaborate my thoughts on why I prefer a "simple" setup for a free AV and therefore give the nod to Panda.
I'm the kind of guy that cannot be bothered with popups and slowdowns. I do not like layered security. I either want to run a Free AV or a pay-for IS suite and be done with it. Speed is very important to me. If a computer is slow - I will not use it, plain and simple. For me I'd rather have a faster PC and basic security than a slower PC that is tough as nails. I'm all about speed. I do CCleaner, Registry Cleaner, and Defrag once every couple days because even the lightest slowdown wigs me out like something you couldn't imagine. I'm a stickler for having a super fast computer and when you run a heavy program LET ALONE a whole bunch of them, system speed goes down dramatically.
I prefer Panda because it's simple, has very high detection rates, and is never nagging me. Now I am a Kaspersky Internet Security 2012 guy for my own machine and it's very lightweight and is nice and that's what I use on my main machine but on my other machines and my clients and family - all of them use Panda Cloud. It's just something I don't even have to think about. I've never seen someone get infected with Panda. I unfortunately have with Avast. I'm not saying it can't happen with Panda, but I have had 0 problems to date. Don't get me wrong - Avast is a great free antivirus and certainly better than AVG, Avira, MSE, etc but it has two big downfalls. One is resource usage and the other is popups.