Sorry Mark, I'm no help as far as switching from an iPhone, but I've used both the Note 2 and now the Note 3. My wife has the S3, I've been very pleased with the Samsung phones. Everyone always says, 'look how big that screen is, I wouldn't like carrying that thing around'. But after using it for a few months, I don't see how I ever survived with a smaller screen, plus it fits my hand better.
The one factor that kept me away from the iPhone was the inability to swap out batteries. I'm never tied to a charging cable with 2 spare batteries.
Good luck in your search for the right phone!