I have tried Endel for a month and I am torn. Compared to brain.fm (which I also use) it was too monotonous for me. I am more the type for more variety in focus music. This is a personal preference because all in all Endel offers a great variety and is intuitive to use.
The sound is great, the noise-canceling and transparent feature too. But honestly, the first generation of the AirPods fit better in my ears than these ones. Not sure what I am doing wrong, but it's just the way it is for me.