I recently listened to 70 albums by Anthony Braxton, several of them very long, between 2 and 12 CDs. I thought a few of his albums were pretty great as works of art, but I enjoyed exactly one of them (Eugene), and I thought zero of them were accessible enough to include in my guide.
I should also mention that I basically only listened to the albums with original compositions on them. And if you know Braxton, you know these compositions are complicated — e.g. Composition 82, scored for simultaneous performance by four different orchestras. The dude is prolific.
To see which Braxton albums I listened to, Ctrl+F on my (in-progress) jazz guide for “Anthony Braxton’s” (it’s in a footnote).