I did upgrade to iOS 6 yesterday night. It has some new features like a more enhanced Siri, native support for Facebook, a redesigned iTunes and App Store as well as the new Maps from Apple. The file is close to 600 MB and can be installed smoothly over the air. And all the settings and customizations will be maintained.
As far as I can tell, the Maps from Apple are not as detailed as what we had from Google but they are fa r from being unusable. I have noticed a few inconsistencies here as far as Nairobi is concerned but this is not a major issue. Most smaller streets are not labelled as well. But overall, the Apple Maps are much more faster than Google. I think it will take a couple of years for Apple to really catch up to the level of detail that Google Maps has but the Apple Maps is much more neater in terms on design. I haven't tested the 3D features in supported cities but I am told they are really cool.
There are also new features like additional option when a caller calls and you can simply reply by as SMS. Panorama support for photos has also been added to the Camera. There is also the new Passbook App though can't imagine how we will use that in Sub-Sahara Africa.
The App Stores are now more organized and makes it easier to search for Apps, Music, Movies or TV Shows. Music App also redesigned.
Overall, iOS 6 has a cleaner, leaner, brighter design than iOS 5. It also feels a little bit faster than 5.