Great feet and decent speed. Feel is really noteworthy, easy to listen to - ear candy on those great sounding instruments. There's another thread discussing improvisation/spontaneous, Carter's playing goes a long way to define how it's done.
It's strange, but I've actually learned far more from Carter's expositions than I have from his instructional videos. I'll watch a snare demonstration, pick one thing that really catches my interest, and work on it. He's so clean that it's easy to figure out what he's doing, and the parts he plays aren't full of superhuman technical wizardry, they're just well played.