We went the Truxedo Deuce Tonneau Cover.
In addition to the 5th wheel hitch, we also have a 50-gallon fuel tank and a tool box. So, we needed a cover that both cleared everything needed very little space between the fuel tank and front wall of the bed.
It is a soft cover that rolls up, but also has a sweet feature that makes it superior for us - press a small release lever, and the front third of the cover flips back for instant access to the fuel tank when the bed is covered.
I would be remiss if I didn't mention Truxedo's service. We purchased this tonneau in May 2010. When we bought our new 2019 Ram, we had an issue with the tonneau rails fitting the new Gen 4.5 bed. Tuxedo not only sent us new Velcro strips to fit the new truck, they sent us a brand new cover, too.