Using the Left 4 Dead 2 demo, I was able to record some versus footage of the new Left 4 Dead 2 infected.
I added some tips I picked up from playing after about a week so if I got some facts wrong its because this was early on.

I was able to play as the new infected using a plugin a modder made on the Steam forums, *I DID NOT MAKE THIS PLUGIN* There's a video with more detail about it here:
http://www.youtube.com/watch?v=mTKs0xzltec

From my playing I've decided the Jockey is my #1 favorite and the Charger is #2
Jockey because of his insane cackling and awesome ability to control players
and the Charger for just generally being able to pick up a survivor and smash them into the roof above them. He be pro.

More gameplay on the way if you all want it (less info)