Personally i am pushing my MobileMe email to my iPhone. As for work, I am pushing my corporate Exchange email to my iPhone as well.

One major differences between BB and iPhone push email is BB actually fetches the email from your configured email account (Exchange email, Streamyx email etc) and pushes to your BB. Meaning if the BB service fails, so does the push emails even though your email service provider is alive and running. Another thing which worrys me is BB server was located at Canada hosted by RIM (maybe Asia might have its own BB relay server) and since all emails go through RIM, what about privacy??

I am a happy iPhone push email user and at the same time I am supporting some BB users i my company as well. So i would says it all depends on your preference, if you are into those corporate thingy, then get yourself a BB. If you live a balanced life between work and play, then iPhone is the choice.