The Behringer FBD is a very good unit and it simple to operate.
Personally I would go with the FBD over Audyssey because it manages only the frequencies you want it to and it is completely customizable.
REW has a bit of a learning curve. It took me a couple of nights to figure it out and get it set up. Once it is set up though, it makes measuring the room and setting up the FBD very easy.
If you read the Audyssey threads here, it seems to be a real mixed bag in terms of success: works well for some, fails for others.
Audyssey seems to be more for people who want a simplified automated solution.
