In addition to that, Android and iOS handle multitasking completely differently. You can see an example of this by opening up a browser, typing a URL, then immediately (before the page loads) pressing the home button to go back to the home screen. Wait 10 or 20 seconds then go back to the browser.
On Android, the page will have loaded in the background, while on iOS the page will have stopped loading when you went back to the home screen, and will now continue once you go back to the browser.
So it's a bit of a trade off...Android actually has 'true' multitasking while iOS only does for some things (like you can play music and do other things, but as you can see above, it doesn't work for everything).