We used a VuQube for years, but upgraded to the Dish Tailgater earlier this year. Works great with the RV, even used it at the house. We spent the summer on our boat in Friday Harbor, and it worked fine strapped on top of the boat...
That was while we were
tied to the dock. I was surprised that it held the signal through the changing tides. If both of us were on the same side of the boat, it would intermittently lose the signal. I do not think it would work at anchor, where the boat will "sail" around some; we never tried that. We did take the cube down anytime we were moving.
Worked fine in Victoria and Anacortes when we were there, too. You do have to pay attention to any obstructions that might be in the way (sailboat masts, taller boats slipped alongside you). If you put the cube out on the dock, you will lose the signal every time anyone walks by it (we dealt with that with our previous VuQube that we kept on the dock at Friday Harbor).
The older VuQube and SD receiver were amazingly simple to use. We only updated because All American Direct discontinued the network feeds - if you want to get local networks through Dish, you have to have a receiver capable of that (our old one wasn't), and call them when you move to a different service area. The Tailgater is automatic: set it down with the handle facing north and it finds the satellites; automatically switches between the satellites as you change channels, if necessary (also receives HD channels). With the older VuQube, you use a remote to line up the dish inside the cube... much easier than it sounds. With the RV, I would put out the VuQube, and Joan would have the signal before I got the other utilities hooked up (usually a minute or two). The automatic Tailgater takes a bit longer to find the satellites.
I find it an easy way to get Dish when traveling. Even with an RV that has an automatic dish on top, there are times you are parked in the trees and cannot get a clear shot at the satellites - the VuQube or Tailgater allows you to place the cube away from the RV (or boat) where you can get a clear signal.
Hope that helps,
Jim