Folks over JBN have post a video show the best 10 featurs of the official released iOS 6. But according their experience, it'not a very necessary update, but like a very solid 5.2 update. Here are the TOP 10 features you will gonna see via the video:

Do Not Disturb Toggle
New Maps
New App Store
Updated Safari
New Phone Improvements
Facebook Integration
Panoramic Camera
Facetime over 3G
Siri on the New iPad & iPod Touch 5G
Updated Mail App

via JBN