I'd go with the iPhone. Comparing BIS to MobileMe is like comparing a Datsun to a Ferrari. BIS offers poor functionality by comparison to what Apple is doing in the consumer space. The other killer is apps. Apple's app store is excellent, lots to choose from and the search and delivery of apps to the device is amazing. RIM don't even know what apps are. Sad to say it as a BlackBerry user of 6 years but, in your case (which is not every case I might add), I think the iPhone is the more suitable solution.