This is why I (we) love Android OS!
Choices...which is also why I love AquaMail. To each his own is a beautiful thing! I'm on the other end of the spectrum from Andrew. I love the material design, how visually fluid and integrated it is, but with the relatively similar layout of the apps. I use my phone all throughout the day to write and send email, read email, work on documents and other work-related tasks. In that regard I consider myself a power user, and I love the FAB, gestures, software buttons and swiping a variety of apps/tasks from all edges of the screen, and in many apps.
I like that AquaMail fully utilizes and make these options available. I love working on a full screen that has no visible controls obstructing my view, but that can be easily and conveniently accessed from the screen's edges or revealed by swiping from within an app. In fact since I'm on Paranoid Android, I don't even have the software buttons (or status bar) on the screen unless I swipe them from the edge when I need them.
I consider Kostya a brilliant developer who with AquaMail truly captures choices, which is the hallmark of Android. "Be together, not the same".