No surprise. The iPhone OS only has minimal multitasking, which means more CPU cycles devoted to the input queue, which creates that illusion of smoothness. Every multitasking OS divides cycles, which doesn't render them as smooth, but they do multitask. If the iPhone OS is going to multitask more apps, its not going to be that smooth either. Please note that the iPhone OS, because it does not multitask third party apps, devotes more memory space for the primary third party application. Android simply does more under the hood than the iPhone.
The question for Apple is how are they going to transition the Iphone OS to multitasking without breaking those 120k+ apps.
Work wise, I find working on the Android a lot faster than the iPhone OS, which I have had experience since 2007. Mainly because I can switch among apps a lot faster, instead of closing each down to get to another app by shuffling across different screens. Android puts the most recent six opened apps into one popup window by pressing the Home button long enough.
I also find Android quite a bit more intuitive. The simplest test for a UI is how to move an app icon around the screen in the simplest most common sense manner.
1. Blackberry, Symbian, Windows Mobile - To move an icon around the screen, you have to go down and pull up some corner menu, find and activate some Move command on that menu, go back to the icon then move it around. Definitely unintuitive.
2. iPhone - You have to press on the black space on screen long enough, all the icons will start wiggling, then you can move or delete the icons. Better than the first, but its not intuitive enough. You have to press on the black space between icons on the screen to activate this, you cannot press on the icon itself, which will start the app. All the icons get wiggly, not just the only one you want to move, and you have to press the main button to deactivate.
3. Android - Simply press on the icon you want to move long enough, you get a vibration, the icon sticks to your finger, then just move it around. At the same time, the cabinet tab turns into a garbage can if you want to delete the icon by dragging it there.