The two platforms, iPhone/iOS and whatever/Android, are driving each other higher and higher in performance as they compete.
In the end, it's us consumers that are the real winners.
Meanwhile - I notice you have a Nook color - not sure if you know this, but you can set it up to boot Android, even the latest Honeycomb, right off the SD drive - no compromising your nook for what you bought it for.
If you stay with your iP4, you might want to consider going that route for your nook so you can keep your hand in Android and see for yourself what's up from time to time. Just a thought.
PS - Lots of folks around here are working with Exchange mail on Android - I access my company's non-Exchange email servers with no sweat (IMAP or POP). What's the odd thing about your company email?