Iphone 5, update from iOS 7 to iOS 8.1.3 ?

[iMore Question]

My iPhone 5 is running fine on iOS 7. I don't have a compelling need for iOS8. However, there are some nice things that iOS8 has that might tempt me to update the OS.
1) Camera is much improved in iOS8
2) Microsoft Outlook requires iOS8

Is it worth to update ?
How is the battery life of iOS 8 as compared to iOS7 for iPhone5 ?
How is the performance of iOS 8 as compared to iOS7 for iPhone5 ?

Please note, these questions are specific to iPhone 5.
Thanks in advance for all the help and advise.

 

[kch50428]

If you want apps that require iOS8 that pretty much makes the decision easy...