I was recently in the market for a second PS3 controller so I could enjoy the multi player modes on my games. I didn't really have $50 for a original PS3 controller so when I saw a MadCatz version of the PS3 controller in the clearance at Blockbuster, I swiped it up.
There are two draw backs to this controller that I've found. One, it's a little bulk compared to the original controllers. Two, it requires two AA batteries to run. Other than that, it runs the same way as the original PS3 controller and is even wireless with a USB receiver.
Not only have a used it on my PS3, but my computer as well. With the PS3 controller I found I had to download drives to make the controller work on my PC. The MadCatz worked automatically without a fuss.
It's an awesome little investment that works great for those who can't afford the real thing!