This is the 360 pad that comes with the slim console. The distinguishing feature is the black d-pad rather than a grey circular one. Overall it feels more comfortable than the original 360 pad, but the most noticeable improvement is the d-pad. The directions are more defined, with rigid edges which aren't as slight as the original, and the d-pad doesn't slide around like the non slim's dpad did.
I play street fighter 4 on both xbox and ps3 and disliked playing the 360 version on pad because of the flimsy poor excuse for a d-pad. However, using this pad I was immediately at home, pulling off special moves with ease, (something i struggle to do with the analague stick or the non slim pad, even though i am series veteran).
If you're getting a 360 wireless pad get this one, it's just better. I'm sure Microsoft will phase out the old ones anyway.