Right. Basically, how do I set this up for the iPhone? I have to choose one of the transports, given experience with them on the iPhone and how the iPhone mail client works (or doesn't) which should I use?

I didn't care which as long as the end result is manageable.

1. The setup problem with the iPhone account, apart from push/notification is resolved.

2. iTunes doesn't do any content sync for mail.

Result is that imap is the only thing that can work.