I've played fps's, including the Unreal Tournament series, for years using a keyboard and mouse. I love the responsiveness of the aiming and the ability to put the crosshair exactly wherever I need to and as quickly as I need to. I gave this a try using a keyboard and mouse for UT3 on the PS3 and was greatly disappointed. The mouse was not nearly responsive enough. There seemed to be many frames of lag between moving the mouse and seeing the result on screen. It was like aiming with a wet noodle. I've tried a few different mice and settings to no avail. At least with the PC there was usually some work around for this situation, such as turning down max pre-rendered frames to 1 or 0. Unless this issue is fixed I would honestly rather use a gamepad for FPS's on the PS3. I believe this is part of the reason the keyboard + mouse controls never caught on for the PS3.