Today I have updated my Android studio from 1.5 to 2.0. No surprising issues. everything seems fine. 2.0 seems matured and I love the Instant Run feature. its Cool feature and saves time in your build and deploy. I have tested against simulator and actual device, its pretty fast. It retains the activity and deploys the changes instantly.
Refer Google Link Android Studio Link for more information.
I loved it. Hope you too like it. Happy coding 🙂