I've played and beat both, and I believe Infamous is loads better. Prototype isn't a bad game, but it gets stale pretty quick in comparison to Infamous I think. For me Infamous always stayed fun, Prototype has the better "open world" kinda thing going on where you can cause mass mayhem and such, but only slightly better than you can in Infamous. Infamous is a lot more clean and smooth. To me Infamous is a buy, Prototype is a rental. Soon as I beat Prototype I traded it in. I still have Infamous and though I haven't played it in a little bit, I have every intention on playing it again. After beating Prototype I thought "meh."