I love my PS3. I've spent hours with the thing, but when it comes to shooters, I have to admit that I usually spend a little more time on the Xbox 360 - and it's purely down to the controller. I prefer the Xbox controller when it comes to FPS titles.
This is why I've really fallen in love with the Afterglow. It's a solid, relatively cheap controller, similar to the the 360 controller in layout, with analogue sticks and triggers that work far better for shooters than your traditional SIXAXIS or DualShock 3 controller.
It also friggin lights up. Just as an added bonus!