I have an iPhone 4s and a Galaxy Tab 10.1, the iPhone absolutely destroys the Galaxy for speed, reliability, stability, ease of use and quality of apps.
The only reason I gave the Android a try was because it was cheaper, I will replace it with an iPad next.
People go on about how there are more apps available for android, but the quality of most of those apps is terrible, and using the same app on iOS and Android back to back is chalk and cheese, the iOS app will always feel smarter, faster and better thought out.

The new S4 looks cool as a phone though, and it is pretty tempting to head that way if Apple doesn't make some big improvements for the 5s.