A hitch selection depends on how you are going to use the trailer and your specific trailer's towing dynamics (they all differ). I divide fifth wheel hitches into two categories, solid hook-up and energy absorbing.
Solid hook-up hitches are good for short hauls or if you are fortunate enough to live where there are smooth roads. They are almost all quality products and will get your trailer to point B from point A.
Energy absorbing hitches such as air hitches and those with rubber springs do more. They isolate the tow vehicle from the forces created when a ton of weight is bouncing around in the bed of your truck. I see an air hitch for those with bad trailer dynamics, bad roads, or planned long tows. In my mind, the comfort makes them worth their high costs.
Another category would be hitches designed for short bed trucks such as sliders and auto sliders. You can check those off your list at the outset. There are a couple of manufacturers of lightweight hitches to help if you are bumping into your payload capacities.