My understanding on this is that they are doing a limited rollout in select areas in order to get more feedback so they can tweak it for final full release which is expected this summer. I do not however know what those select areas are or how you can get one if you are in those areas.
If you are one of those folks selected, please be sure to post about it here, and if you have any questions you can post them here as well, and we have been told by DISH that we can answer those question. With that said we are very limited at what we can say about it until it is in the publics hands.
But with what HipKat has posted above, I must say I am disappointed there is no Dolby Vision support on these boxes. Even some of the cheap Android boxes at Walmart now support those standards now.