I personally think a keyboard is really good for fps games. Although the keyboard keys lack in precision (only presses or not pressed) i think its easier than a controller.
If you look at the G13, it seems that u'd have to constantly check where your fingers are on the myriad of keys, with a regular keyboard, this is a bit easier. Additionally, i feel that the mouse has the best control compared to any joystick. You get full control with your hand, not just your finger. Mice are accurate and really easy to control in any direction, and it just feels more natural compared to a joystick.
But this is only my opinion, if you need something other than your standard keyboard+mouse, get a gaming keyboard and/or mouse, not one of those silly button-loaded pads.
i finished my first build in may. before that i was only a console gamer. it took a little to get use to the keyboard but now i have no problems. just get a good quality keyboard and u will figure it out fast. and a mouse would be 100x better than that thumbstick
I use the G13 and love it. As for the thumbstick, I do not use if for movement. It just doesn't feel very natual to me. I use the main keys that correspond to the WSAD keys for movement.
What I do use the thumbstick for is quick weapon swapping. Works great. For a game like BF3, I have 'up' as the primary weapon, 'down' as the rocket launcher, 'left' is secondary weapon (pistol), and 'right' is special weapons such as mines. Works great if I'm in a firefight and run out of ammo - just quickswap over to my pistol and finish him off.