I did make the switch. I love my iPhone, I was worried there would be a learning curve, but I hit the ground running with it and haven't had any problems.
I wanted to share pictures with my Dad, so I just connected my iPhone to his computer (PC) and he was able to upload them without any problems. I wasn't able to sync my contacts like I would have had I kept the Android system, but my contacts did transfer, just not their phone numbers.
I was torn between it and the GS3 and I ultimately decided I didn't want a phone as big as the GS3.