I will add my opinion to the Sidewinder. I had no choice but to use this because I have the RAM Box on my truck. I was told that I couldn't do a 5th wheel because of the Ram Box. The Sidewinder works perfect along with a standard Reese hitch, and my 5th wheel doesn't even come close to hitting the truck cab or side of the bed. I have a Mega cab short bed. I think Reese came up with this because of the short bed trucks and no need for a slider. I love this system, although, as mentioned you have to get used to hitching and unhitching. You must come in straight to hitch. Don't apply the emergency brake when you are unhitching. Some practice and it will be fine. In my situation, this was the absolute best solution to getting a 5th wheel.
Note: I might want to add some advice. Check those 4 bolts on top of the swivel each time you check your wheel lug nuts, and make sure they are at 45 foot lbs. They do have a tendency to come loose. Maybe a drop of blue locktite will solve this.