I spent two years working for NOC on the Ocoee. As a company, I feel that they really have it together. The Ocoee is a really busy river, and they did a great job of training the staff and getting the job done. It was also a really fun place to work.
The Chatooga is a great river, is is the most remote, scenic, and exciting river that the NOC runs in my opinion. The problem is that there has been a drought and it runs very, very low in the summers, and all of the getting out and pushing your raft over the shallows takes the fun level down a bit.
The Ocoee is dam controlled, so there is consistent water, and the whitewater is fun. The problem is that it is a zoo. Full on combat rafting.