I used one of those new UPS dollies a few days ago with the springs mounted under the 5th and I have to say aside from being nice and shiny I was not at all impressed. They are quite heavy to lift and maneuver and seem more jumpy going down the road. Of course, I lost my nice air-ride dolly courtesy of Motor Cargo a week ago, so anything may seem bad compared to that...any thoughts on these new dollies?