Going from the 4S...I'm surprised that the poll is a close between the 4 and 4S as it is...I thought a lot of people skipped the 4S and would be going from the 4.
I've been doing it since the 3GS but the rest of that statement is true lol. So yeah I'm upgrading from a 4S....well I traded it for a Galaxy S3 a few weeks ago but I'm coming back to the herd lol.
Going from iPhone 4, and part of the reason I'm excited is, I am sick of the keyboard lag typing on forums (full site not mobile). Also can't wait to have Siri for the first time.
I changed from iPhone 3g to the Samsung Galaxy Captivate. After a bad year with the phone I switched to a Blackberry Torch. I like my Blackberry but I REALLY cannot wait for my iPhone 5 to get here!
I don't understand people who upgrade their phones every single year. Sure each update usually has at least one or two nice features but phones generally last pretty well for two years. Upgrading from the 4 here