Wow, what a coincidence. I just happened to beat the game with the good ending a couple days ago. I was impressed with how good the game was. It's definitely one of my top PS3 exclusive games. I don't know how I would rank it, but probably top 10 PS3 exclusives, maybe top 5. I also didn't get bored with the game. I wasn't interested enough in it to finish even half the sidequests, but the main plot and most of it's missions were great. It's definitely my favorite free roaming game this generation (I've played Assassin's Creed 1, GTA4, Crackdown, Saint's Row 2 this gen).
There were a couple things that bothered me about the game. First off, the framerate could get atrocious at times. I'm talking borderline slide show. Overall the graphics were good though. The only other complaint I really have are the controls. I would have preferred a weapon wheel to select what power to use as R2. Having to constantly switch between the right stick and the face buttons was annoying. Actually, one more complaint is the enemy design. Pretty boring IMO.
The story was great though. Only thing is that it was more like InFamous: Prologue. I can't wait for InFamous 2 though. Improve the framerate, maybe modify the controls, and get a little more creative with the enemy design, and it'll be a great game. In the meantime, I'll be replaying the game, this time evil.