Android = open source to a degree
iOs = closed they want monies for everything
wp7 = closed and if you like accessing apps forget this.
Meego = unproven and since its gonna be run by Nokia expect neglect

For me i like apps, videos & music so a 32GB Galaxy tab would be my choice but then again its phiscally huge and expensive.

The camera on the tab sux compared to virtually any Nokia phone which Nokia is known for making great cams for there phones.

The galaxy basically has massive amounts of games if you add emulators snes, genesis, android market & so on and so forth.

Major downside for my is it does not have a keyboard.

I'am seriously thinking of getting one myself but even if i do i'll keep my N900 to still use since its a great tablet/phone.