Um ... the iPhone does Push.
Sure it's with Yahoo, but it's still Push. Oh, and how does it take less battery than IMAP? I'm not an Apple apologist, I've managed large-scale Windows networks, including BES on Exchange for instance, but I don't get how people want to find fault with anything Apple these days.
The iPhone doesn't do Push Exchange Sync? Whoop de doo, it'll still do what ever mail syncing I want with my servers and accounts. If I want Push, I just write hardcore Procmail rules (or use an off-the-shelf system any sysadmin can do for you) and selectively forward to my Yahoo. If you're not techie enough to do this or don't have a sysadmin managing your mail server, you're not going to lose out as you've not got a corporate exchange server in the first place.
Sure, the iPhone has failings, but not being a Blackberry is not one of them.
"No wireless. Less space than a nomad. Lame." - CmdrTaco, Slashdot, on the release of the iPod, October 2001.