I have the Power Mover brand that I have been using for a couple of years. My opinion is the trailer valet will not work well moving any trailer with real weight. I have my boat trailer that I move in and out of my garage 1-2 times a week starting from May-Oct. My boat trailer/boat are about 5000lbs. The largest problem with all of the movers is they have the tendency to slip and/or tilt over. My AC-8 (
Power Mover) has four wheels and my driveway is just slightly tilted (about 4% incline for 35ft). The power mover has a mount that you attach as far toward the rear of the trailer as you can get it (to add more weight to the top of the power mover for traction). I still have problems with the four wheels slipping every now and then. I have also had the mover slightly tilt when I didn't have the mount tightened really well the first time. The point is, there is a lot of stress on the power mover when trying to turn.
Now, the trailer valet may work if you are only trying to move your trailer a couple of feet on level ground, but my guess is you will have real issues if you are trying to move farther than that or up any incline. The lack of wheels for traction and the small width on the footprint will be a problem.
Just want to give my opinion before anyone buys these - things to thing about.
2014 Jayco Jayflight 32BHDS
2015 Ford F250 Lariat 4x4 Crew Cab 6.7L Powerstroke