Firstly, this is available to buy now, I bought it from a US shop just before New years eve through the Amazon "used and new" option under the Amazon list price.
The box set is beautifully presented, and, as someone who has been after these shows for a long time, these CDs are well worth the wait!
The sound quality is amazing, yes the mix is different to the Live Evil version of the live bits used, but it isn't that different.
I've had Live Evil for a long time now and it has burned itself into my DNA, the biggest thrill of this box set is hearing the music as it was played without the editing that appeared on Live Evil. It completes the picture, so to speak, of what was played at the Cellar Door run.
I would recommend this set to anyone who loves Live Evil, and if you haven't heard Live Evil, yet like the electric era Miles (or are new to both), buy with confidence!