Getting the HTC M9

Hi guys, I'm using HTC M8 and I'm thinking about upgrading to M9 (I have a good deal). I've heard that M9 had a lot of issues when it was released, so I'm looking for someone who's been using it from the day it was released to ask a few questions:

- Did updates fix anything?
- Is camera better now?
- Is rear camera better than M8's camera, if you ignore the resolution?
- Is camera at night better, or is it completely useless?
- Does it overheat like before?
- Is battery life better than before?

Thank you a lot. Sorry for my english.