No Party functionality, no out of the box voip (you dont get a headset with the PS3 you need to buy it seperately). I did that to play MAG online and the entire experience from trying to get into a MP game to trying to get the thing to pick up my special PS3 blutooth headset to talking with other players sucked. On Xbox live if me and my good friends Murph & Grimspoon decided its time for a bit of fucking around in NFS Hot Pursuit we I hit my guide button, invite to party and I am talking with them, without issues, in under 60 second. To get them into my games is usually only a press of the X button away and most games with an online functionality has this feature.
Next up the Store: The PSN store is slow (Even on my 20mb line) and the interface retarded. Having to first add money to some wallet before I can purchase the game is almost as stupid as MS's MSPoint System. Atleast on the xbox it comes up with a messages saying "Add More Points" if you are on the purchase screen for an item.
Overall the PSN seems to miss the entire point of an online service, to provide a easy & effective service for player to be social with whoever they want.
I enjoy playing games on both my consoles (and my MacBook Pro) but I prefer playing Online on my xbox. Sure I have to pay for it but at the service offers functionality that works and has over the years provided me with significantly less issues than my various attempts to get a similar experience out of the PS3 online.