I just bought a second-hand Fitbit Charge 2, and immediately discovered how wildly inaccurate it was at measuring my heart rate, vastly undershooting it by 20 or 30 bpm. No matter how I adjust the way I wear it, I can’t get a good measurement that I can rely on. This was a bad purchase decision.

Most assuredly, the best experience is going to be on the 12.9-inch iPad Pro. Less scrolling. And there is a LOT of scrolling. The app is beautiful, and works as advertised.

Grain doesn’t compress well.