Ken is right. I have both the B&W turnover ball gooseneck hitch and the companion fifth wheel. I would not choose anything else. I simply pull the slide pin under the wheel well, pull the gooseneck ball, turn it over, and you have complete use of the bed with no rails, and it takes all of 30 seconds. The companion 5th wheel is great. I can put it in or take it out in about 5 minutes. I have no experience with anything else, but I have no reason to go with any other hitch. It all mounts from underneath and is extremely well built.
PP - Let me know if you want to look at the hitch setup sometime.