Listed pretty frequently on eBay. I got overly excited when I found one locally (Amoeba in SF) and over paid on a copy that looked pretty good in the dim light there. I ripped the first side and did a quick de-click and decode. Sound was muddy and the mix uninspired - rhythm in the back, all the rest up front. I thought maybe they'd bounce some of those trumpet echoes around - they do, but only in the front, which is what is done in the stereo.
I've read that the original versions were pretty muddy and that the box set was the first reasonable sounding version out there (which is where I came in), this may turn out to be true. Since my copy is going to require some effort to clean up and I wasn't impressed with what I've heard so far, it's pretty low on my list of projects. Too bad, it could have been a great multichannel SACD with an aggressive new mix.
I've heard that Jack Johnson was remixed for surround SACD then shelved (at least for now), so hopefully someday a deserving surround mix of Miles Davis will be released.