The answer really depends on the kind of person you are. I would say that in a nutshell, Android is like Windows PCs and iPhone is like OS X Mac PCs.
You have more options and customization on Android. The highest end Android devices have better specifications than the latest iPhone. I find the four face buttons to make a lot more sense than having a single home button when it comes to interface navigation. Because of all of the power Android gives you, it is possible to mess the device up from settings or installing certain software. Because of how easy it is to get an application put up on the Android Market, there's an uncomfortably large number of defective applications. It's incredibly easy to destroy your battery life because there are a large number of Android apps that do not have a properly configured sleep mode so they consume battery even after you close them. With Android, just like Windows, you have to monitor to some extent what your machine is doing. It is capable of unlimited multi tasking, so if you accidentally leave all of your apps running instead of closing them, you will notice a severe drop in battery life. There are a surprisingly large number of people that don't know the difference between exiting an app with the Home button and exiting an app with the Back button on Android.
iOS devices are easier to use, it's not really possible to mess them up software wise unless you go the jailbreaking route because the app store is locked down tight. You don't really have to worry about running too many things and draining the battery and you don't really have to worry about applications draining the battery at all just by being installed like some do on Android(At least in my experience).
It's my opinion that if you know what you are doing or are willing to learn what you're doing, Android is the better platform. If you want something that works straight out of the box without messing with settings and carefully selecting and testing applications, you want iPhone.