And how many aim to deliver a streamlined, easy to use experience for everyone? Not geeks, not people who demand a full OS at all times, but everyone. Computer illiterate moms, uncles who can't figure out how to upgrade their Google (browser), and so on.
How many of them have the media consumption capabilities of this thing? Again, not for geeks who want to rip their own Blu Rays, or *gasp* play downloaded stuff, but someone who doesn't mind buying a movie on iTunes, or the iBookstore. How many of them aim to make casual use more refined and dare I say enjoyable?
No Android OS I've seen has this level of polish, and this appealing a size/price point. On top of that, you have all the stores I mentioned, right there on the device.