A curator at work (bl.uk) offered to get a limited edition box a while back. Delays from China, and the result was a little disappointing: the box is sort of MDF with a covering which isn't properly glued. The images and designs were great, as is the book inside, but all the discs were in cardboard sleeves (they'll never learn). There were only the 16 CDs and DVD. The USB has a number of extra tracks that follow on from disc 16 and are itemised in a rather hurried A4 listing. They are, however, essential for completists, since along with demos etc., there are a couple of used-in-film cues they didn't include just because they didn't fit on the CD. In trying to catalogue this item, I'd end up having to assemble cues from as many as 4 sources for some films. As such it's a bit of a mess. Some discs attempt to interfile extra cues with existing released tracks, and others just plonk them at the end.
The only difference is that the limited edition comes with a certificate of authenticity. One perk through ordering the limited edition through the Warner Brothers website was since it didn't come... more