Ever since I got into jazz, my answer to "what is Coltrane's best album" has always been to reflexively say A Love Supreme. And it's not the wrong answer by any means. A Love Supreme could be a legitimate answer to a number of other questions - the best modal jazz album, the best jazz album, or even the best album.
But recently, I am starting to think that Olé is my favorite Coltrane. The title track is just such a wonderful tour de force, with perhaps one of the best rhythm tracks in all of jazz: twin bass and the brilliant Elvin Jones on drums, with the occasional McCoy Tyner fill, create a such a simple and yet pulsating rhythm that somehow manages to carry the piece for all of its 18 minutes. There is a little interlude at around the 8 minute mark when the two bass players, Art Davis and Reggie Workman, play off each other for quite a bit, it's just beautiful.
The rhythm section really allows the 7-piece band to shine. And what a band that was, with McCoy Tyner on piano as I mentioned, Freddie Hubbard on trumpet, and Eric Dolphy on flute/alto, though he is credited under a different name due to copyrights. This is what makes the recording for me: it is a true ensemble effort. Perhaps one of the few times in which Coltrane the band leader was more interesting than Coltrane the virtuoso. He is so restrained, allowing the music to breathe (perhaps the closest he's been to Miles?), giving space for the other instruments to leave their mark (Tyner's solos are particularly beautiful). Coltrane's restraint makes his appearances in the record even more remarkable. He's also mostly in a tender mood throughout, not near his Ascension or Interstellar style, but with carefully chosen moments of aggression, his final solo at the end of Olé being perhaps the emotional peak of the album. Just a fantastic piece of music.