One thing to be aware of is that Directv announced at their dealer conference that standard definition channels will be turned off in 2019. Currently standard definition is the only content that in motion domes can receive from DirecTV.
That being said, no one knows what will happen when that time comes. The pessimistic view is that all current in-motion domes no longer function with DirecTV. The optimistic view is that the satellites currently broadcasting in SD aren't going away after 2019 so it's possible that Directv will shift HD content to the current SD positions thus making our domes capable of receiving HD with a receiver change.
Other than the fact that SD is being turned off in 2019 the rest is speculation. You should know that going into a purchasing decision though.