When upgrading to 6.0 on an iphone4, your phone will get extremely slow. As a 4s user, I will not upgrade to 6.0 for the following: 1: They removed YouTube; 2: Google maps works with everything and all apps. It's going to take time before all those apps get on board with applemaps. 3: the phone screen went from easy-to-read black with bold white numbers to white background with fine-lined black numbers which are more difficult to read. 4: the app store now displays a full-screen for each related app. So if there are 100 apps related to your search, you will get to slowly search page by page. 5: It is very slow on iphone 4 and should probably not be used on it. There doesn't appear to be a downgrade option. I really loved my iphone, but now I don't think I will buy another one. I won't upgrade my 4s so it will soon become obsolete. The iphone5 has all different accessories; might as well try a new phone when I am due for upgrade.