I must preface my opinion with the fact that I do not own a PS3 nor have I spent more than 2 hours on PSN myself. That said, I have spent at a minimum 50 hours watching a friend of mine play various games on PSN, so I feel that I am capable of giving my opinion on the subject.
Obviously I prefer XBL over PSN. My primary reasons are that few PSN users seem to use voice chat, I noticed no ability to "avoid or prefer" specific users, I thought that the download times and the browsing of arcade styled games on PSN seemed 2nd rate in comparison (ease/speed of use), and I also thought that entirely too many folks on the PSN friends list had the same avatars.
I would say that while the PSN is free, I have never had an issue with the XBL subsciption simply based off the excellence of the product. If seeing PSN in action gave me the impression that it was on par with XBL, then I might feel ripped off. For me, having an online service is about alot more than just playing the games, it is also about being in an online community. This includes party chat, game comparison, user ID cards, played game comparisons, game demoes, movie services, text/voice messaging, diverse avatars, etc.. all of which XBL provides for me.
