iOS 7 is here - at least the developer preview. I installed yesterday and had almost no issues with this early version. The occasional App hang - but nothing that couldn't be resolved by reboot or App re-install.
The new desgin is great and the new functionality coming with this upgrade has been overdue.
The Control Center is in particular useful and I am not sure how I lived without it until now.
iTunes Radio is the other big one for me, as I like the integration with my music library.
I will write up some more in depth posts in the coming weeks looking at the new features in detail.