I purchased the box set, primarily for the 5.1. It's DD and has the same tracklist as the RBCD. Sounds nice, though it would have been better lossless. Poorly authored - transition from track-to-track is choppy - you can hear a hiccup, and it sometimes snips a bit of the start of the track. The track listing is spread over several screens, but does not advance when you get to the end of a page. If you click on 'next,' it takes you to the next screen, but stops the 'play all' function - i.e. you have to highlight and click each track individually to play it (and, again, it cuts off the beginnings of the tracks).
Extras are 'eh'. 12x24 poster, facsimile of a score page with a printed 'autograph,' two film cels (they and the score page are apparently identical in all boxes). Besides the 5.1. DVD, only things really of note are an EP with a few bonus tracks not on the standard RB release, and a 7" vinyl picture disk. Cheap packaging - discs are not secured.
Overall, a quickie cash-in to get a few extra $ from the fans. Unfortunately, they suckered in this fan of both 5.1 mixes and film scores. Wish they had just released the surround music disc w/o the tchotchkes (and decently authored).
BTW, the score itself is magnificent. I was disappointed when I heard that Williams had not been invited back to finish the series, but after hearing it, I think the producers made a grand choice.