My thoughts about the album are a bit mixed, Sketches is easily the least jazzy of the collaborations; also I feel that Miles' own playing is not quite "just a bit" up to the standard of the previously recorded Evans collaboration Porgy & Bess. Miles really put himself out on a limb on Sketches, his vulnerable stark sound was made for this music.
It is well known Miles had trouble on this session, the strange new material, and the tough Evan's arrangements physically exhausted Miles, he did not record again for over a year after the session.
Sketches of Spain is an album that will grow on you after repeated listens, the brooding mood of the piece is hard to ignore. Personally my favorite track is "Solea," I love the bass groove on this track, really puts you in the ring with the bull fighter.
Sketches of Spain on vinyl like most Miles Columbia releases are readily available at reasonable prices. You could get a near mint 60's Columbia 6 eye copy for around 15 dollars.
A 66 year old record like that is certainly a piece of history worth having. The reissue may sound as good or better, but they can't mimic the feel of that aged thick cardboard. Them old Columbia records hold up well to surface wear too. You could get a VG to VG+ copy for under 10 bucks, maybe better than that in a local record shop.