[mgmueller]

Android Market vs. iTunes:
iTunes has a bigger selection of apps.
But in all other areas, the Android market beats iTunes hands down.
I've already mentioned the possibility, to get a full refund (no questions asked) in the Android market, whereas iTunes even for faulty apps states "not our responsibility, please contact the developer".
But there are tons of other advantages:
- When scrolling the Android market, you see a note for all the apps you've already purchased. In iTunes you only see this for the ones you've installed right now on the respective iPad/iPod/iPhone.
You can re-download from the Android market anytime, as often as you want. In iTunes you can re-purchase. If you already own it, you can re-download it for free. But as you don't see any comment for the apps you don't have installed already right now, that's just kind of guesswork.
- Most of you probably already know, but just to have mentioned it: Android isn't exclusively bound to the Android market. There are apps for opening other markets and you simply can download files within the Android browser and directly install them, similar to .exe-files on PCs.
Meaning: On Android, apps can't be banned. You always can download from other sources.
iTunes on the other hand is a closed system. You can use "Cydia" and the likes, but you have to jailbreak your unit for that. Way more complicated and way less options.

Accessories:
That's not about the OS, but aims for the hardware. Still, very important in my opinion.
Samsung is a disaster in that area. Surprisingly, Dell isn't much better. For example, even 8 weeks after having bought Samsung Galaxy Tab, the official Samsung covers still aren't available from most sources, i. e. Amazon Germany.
Apple on the other hand is (as we all very well know) marketing genius. Their own accessories had been available at they very same moment as iPad. And there are tons of 3rd party suppliers.
You've got way more options for iPad. And those options are available "right now".