I've been listening to this since October 2016 (it was a somewhat-hidden bonus track on A Moon Shaped Pool). I think it's amazing, it helps me focus and the build-up is satisfying. Personal anecdote: I was listening to this on loop while I was working on my final university project (computer science -- a robot which learns to play old computer games better than humans ;-) ).
Understand why it didn't make the final cut of A Moon Shaped Pool but a great track nevertheless.
Music magic once again!