We've had DirecTV since the 1990s, and we have it in the RV. However, to get HD service with DirecTV, you need a roof-mounted system such as our Winegard SK-SWM3 automatic dish. NONE of the carry-out dishes will give you DirecTV HD service. You could, however, use a Slimline multiple LNB SWM dish on a tripod if you want to set it up every time you move.
That's not the case with Dish - HD service is available with capable carry-out dish systems.
So, it depends what capabilities you want and what you're willing to spend.
Rusty