That is the fault of Infinity Ward for glitched lobbies, and both are a common occurence on 360 and PS3. PSN as a matchmaking service has no bearing on the game being glitched by the users. Infinity Ward has already stated that they can't fix it and tried passing the buck onto the PSN, while the same problem has yet to be patched on Xbox Live as well. And having owned MW2 on 360 and PS3, the differences in multiplayer begins and ends at the console's home screen. After that, you wouldn't know you were on Xbox Live or Playstation Network if the MW2 multiplayer screen didn't tell you.