use them both until you find which one you like. But c'mon is it really that hard to put a snipit into your code? Thats the only real complaint I've gathered from GA.
I use both actually it's fun to see how different the information is between the two. So basically i look at the averages. But with google i know it was from what ads so that's good.
But my real question is, which one is more accurate in giving the number of real visitors? I need this to tell private advertisers and of course it has to be accurate (if awstats include bots/spiders, then it's not accurate)