I am someone who went from Android to iOS. Why? Because it works. Way back in the day, I used Windows Mobile phones, bought my first one in 2003. WM sucked hard, but with some tweaking, it was bearable. I went to Blackberry for a year (dont ask) before going to Android. What I saw with Android is exactly what I saw with WM. Each hardware version needs to be optimized for the OS, so who knows exactly when, if ever, your phone will be updated. Sure, I rooted and ran custom ROMs, but the carriers and manufacturers are locking down phones, so that's not really an option. One of the very first apps I put on my Android phone was a task manager. I looked around for the best free task manager and downloaded it from the app store. Problem was, I downloaded a task manager that had a very similar name to the one I was looking for, and since I didnt read the terms and conditions of the app, I failed to realize it signed me up for a $10/month text messaging service automatically that took over 2 months to finally completly get rid of all the messages and charges. When I buy an app from Apple's app store, apps dont sign you up for stuff automatically. If something requires a subscription or in app purchases, I have to authorize that app, not just have some little blub in the terms and conditions that I frankly will never read anyway.
If an when there is an Android phone that works with my carrier that will allow me to update it in a timely manner of a new OS release that I don't have to worry about being useless before I can get another subsidized phone, I'll go back. At least with my iPhone 4, I don't have to worry about software updates for a couple of years. I know I will get iOS 5, and by the time iOS 6 rolls around, even if I can't update my current phone, I will at least be able to get another subsidized phone.