I've had this album for quite a while, and honestly, I feel it's overrated. I started listening to Miles pretty much when I started listening to jazz. I was directed of course to buy Kind of Blue (absolutely superb) and Bitches Brew (extremely overrated).
I feel that because this is a transitional album, where the new band hadn't completely gotten their groove yet, and the second great quintet is on its last gasps, that even though I find this to be just a hint above average, it is still an intriguing and complex album, and should definitely be heard.
This ablum should be complemented with "Miles in the Sky", (performed almost exclusively by the quintet, with George Benson guesting on one song) which is the more focused, and I believe better, of the two transitional era albums.