If the sat service is only for your RV and you're not a full-timer, then Dish is the way to go. Dish has a very RV centric "Pay-As-You-Go" service that lets you start and stop service with no penalties and no contract. You do have to buy your equipment though. There are several different equipment packages available from
DISHforMyRV.com, but a little research may find better prices elsewhere. Which receiver and dish will work best for you would depend on a better understanding of what you want from the service. Dish has DVR receivers that can record up to 16+ channels at once for instance, and others that only receive one or two channels.