That's exactly what it is. It's gamefly for digital stuff and it's a grab bag that you don't get to pick from. But you get to enjoy the games from start to finish, rack up the trophies from them, and keep permanently all the themes, avatars, demos, and anything you buy at discount (full games, dlcs), so it might be worth it.
I went for the 15 month for $50 because I wanted to give it as long as possible to see if it can pay for itself. I'm guessing the majority of the stuff will suck and I'll never get to it, but there should still be some neat games. I'm not buying ANYTHING day 1 on PSN anymore though so I can wait and see if it becomes a free PSN game down the line. Bionic Rearmed 2, Explodeman, etc...all wait and see now. If they go on sale for cheap I'll grab them, but no more day 1s. I want to get my free crap out of this.