Question [Q]Question on Themer App

Hey XDA-Developers Community,
I've browsed this forum multiples of times and finally decided to make an account. I've seen these ads on Themer and everyone's awesome home screen and all. But here are a few question on Themer that I have.
Note: I don't own an Android device at all(or any device), I am asking these questions so when purchasing an Android phone it'll work well.
  1. Will Themer work on any Android Phone/Device?
  2. Will Themer work on the HTC One M8?
  3. Will Themer work on the Google Nexus 5?
  4. Does Themer make my phone waste extra battery?
  5. Does Themer require me to root my phone?
  6. Users that use Themer, describe it in a few sentences

Thank You to anyone who can help clarify my questions and all . Thanks!