My experience with Roadmaster has been excellent, though the Even-Brake style was never my first choice. If your installer is familiar with Roadmaster, then spend a little more on their BrakeMaster, the one I chose and am very happy with. Storing it is certainly easier than a box would be, and set up is no more difficult. Ours has always worked flawlessly. And Roadmaster has been there on several occasions to tweak another installer's work and improve my hitch configuration, all at little or no labor cost at their Portland and Vancouver facilities.
That said, if you like your US Gear system on the smaller car, why not stick with it on the Yukon?
-Joel