Nothing grand, nothing horrible.
Pain is my first taste of a PSN Exclusive game, having recently gained access to a PS3. It really isn't a bad game, to be honest. It is very easy to pick up and play, yet is complex enough to warrant me coming back to it once in a while. Its level design is vibrant and functional, and its characters are quite visibly interesting. However, after playing with it for a while, it starts to to loose its luster a bit, with unclear objectives and excessive pay walls.
Overall, it is worth the initial purchase, though its extensive purchasable add-ons seem quite shallow, with only a few seeming to be worth the money. I would recommend this game to those seeking something to burn short chunks of time with, and not recommend it to those who seek something deeper.