I currently have an iPhone 3GS that I purchased off of Craigslist last June. At the time, I was switching from a BlackBerry Bold 9000. I enjoy using my iPhone and don't have any issues with the phone or the UI.
I am currently eligible for an upgrade with AT&T and have been contemplating getting a Motorola Atrix when it becomes available. It seems like that is the best choice of Android phone on AT&T. I have a family plan and my wife's contract does not expire until May 2012, so switching networks is not an option.
I have an iPad, so I'll still be able to use iOS apps. The only apps I usually use on the go are Twitter, Facebook, and the web; all of which are available on Android. When I'm at home, I usually use the iPad anyway.
What has been the experience of others switching from the iPhone to an Android device? What do you like better and what do you miss most?