How is iOS 6 on the iPhone 4?

Considering whether to upgrade the iPhone 4 or not, two major concerns:

- Many users have reported a serious decrease in battery life, even compared to iOS 5, which was a big step down from iOS 4 already.

- Many users have reported lagging and slower app functionality & loading: Camera, Safari, App Store, Messages, etc.

What is your experience with your iPhone 4? Thank you in advance.