My friend keeps on arguing with me that xbox is better than ps3?

it's getting annoying! there was this dude who i was saying good stuff about the ps3 and why its good to get it, then my friend overhears and takes him away and starts saying that ps3 has no games and online and such. Its funny cause ps3 has lots of things including Home, free online(headsets too), good games, blu ray, etc. but he always says ps3 sucks and it's way overpriced. What should i tell him? it's really annoying, plus it's not like i don't like the 360, but he has some serious issues whenever i say "sony".