Streaming video takes a lot of bandwidth. One movie could go over 2 Gigs and then if the data is slow the movie will stop to reload often. As far as selection, they have a lot of movies and TV shows but nothing brand new. Amazon has a lot of newer programing. When a new movie goes to DVD they might have it available for only a couple of weeks then its gone.
I recently considered dumping SAT but I am having difficulty finding any service that is continuous like regular TV. Amazon, Hulu, Netflix play a show then it ends and you select a different one. Part of the cost of cable and SAT is paying for someone to take the time to set up all the programs to play continuously. Watching a movie is one thing but if you wanted to watch HDTV there would need to be some action between each show. I've heard about Slingbox but that is also a bandwidth hog so I don't know if it is feasible with a MiFi device.