I wanted something to protect the floor of the trailer and garage floor. I bought a set of the skinz covers and the wheels from sure grip. Each has its pros and cons. Pros: Don't tear up the lawn or mark up the concrete. Load easy in the trailer without tearing up the wood. Ski's do stay on well in both forward and reverse. Cons: Does NOT turn at all so good for straight shot purpose only. Harder to put on than the sure grip dolly's.
Overall, I like the dolly's more than the skinz. We will see how they perform first time I have to unload in the snow.
I've had other boots and dollies with my biggest complaint being keeping either on in place over uneven surfaces. These came right out of the box and onto a sled we recently purchased. Drove right up a set of aluminum ramps into the back of my truck. Worked perfectly. Also stayed on well when we pulled the sled out and down the ramps. A little spendy but at least they work well.