One thing to add about the Spelljammer box: all of the B&G boxes come with about 4 extra encounters or mini-adventures to add to the adventure. For the most part, I don't find these necessary, as the WotC adventures are quite long enough, and stuff I add to them is likely to be totally personalized to the PCs, not just additional side quests. However, the extra mini-adventures in the B&G box are all set on the Rock of Bral and balanced for different levels, and imo they are really helpful in enhancing and fleshing out the Rock of Bral, which is otherwise kind of underwritten for such an important place.