For Consumer email, Android and the iPhone offer superior email. They offer full HTML support that rivals desktop quality. I have never had a truncated email, ever on said platforms.
Security wise, they both support exchange out of the box. There are also many security apps available for free and paid as well. iPhone supports remote wipe at this time I believe.
Gmail integration with Android devices is flawless. Gmail is push and arrives instantly. Gmail is also push on the iPhone if you set it up through exchange (unless iOS 4 changed that?)
There is notification of all email, and many Android devices have LED notification as well. You do not have to activate notifications, they are usually automatically on. You can just customize it as much as you like.