Your personal "reference" recordings?

[Woochifer]

Has anyone done any extensive testing of KIND OF BLUE on vinyl vs. CD? I'd be curious to hear some insights on the results.

That would depend on which LP or CD release you're talking about, since Kind of Blue has been reissued so many times on both formats. Currently, I have a LP from the mid-80s and the SACD version. Between these two versions, the SACD is more revealing, more dynamic, and with greater detail than the LP version (at least on my system using my turntable/cartridge combo).

But, these results can vary considerably. The LP version that I own comes from Columbia's digital remaster series, which got criticized at the time for dulling down the original recordings (presumably this was needed because the first CD transfers were done as part of that series, and tried to avoid the harshness and brightness that plagued other early CD releases). At least two other better received LP versions came out after my version -- one of which was a limited edition 180 gram pressing from Columbia, and the other a 200 gram 45 RPM "speed corrected" version from Classic Records. Purists will usually tell you that the earlier pressings for vintage albums dating back to the 50s and/or 60s will usually sound better than reissues pressed during the 70s or 80s -- closer to the first generation master disks, less use of recycled vinyl, thicker plats, less use of gimmicky "simulated stereo" and other heavy-handed processing etc.

Sony has also subsequently reissued Kind of Blue at least twice on CD. I don't know how they compare to the vinyl, but they have also been reworked.

Interestingly, you can't exactly trust that the SACD version will sound superior all the time either. On Miles Davis' In A Silent Way, the digitally remastered LP sounds better than the SACD. Of course, the album's a mediocre recording to begin with, and the SACD seems to highlight the flaws more glaringly than the LP does.