My only complaint (and it’s relatively minor) is that the power button is in the same area as volume and the camera button. I’ll often hit the wrong button on accident.
Other than that, it’s fast, responsive and I feel the UI is light years beyond my previous Droid Maxx. I’d say about 80% of the apps I use are on it. Couple that with a couple of emulators (one of the reasons I dropped iPhone – tired of their restrictive iTunes Store rules) and it pretty much has everything one could need in a smartphone.