They are all good, most of the differences are just different barrel configurations. The Camper is the basic 5.5" model, and prices go up from there.
There are two grip frames though; one uses two piece plastic or wood grips, and the other (URX frame IIRC) uses wraparound rubber grips with finger grooves. They are not interchangeable, so make sure you get the one you want. Mine has the wraparound rubber grip; it's very comfortable in my hands.