I have been saying for ages that the only thing that matters in a tablet is the available content: What can I download to the device, and watch on a plane, train, automobuggie? Everything can stream Netflix, surf the web, etc. The number of downloadable TV shows and movies is by far the most meaningful difference between tablets.
The assumption: iTunes and Amazon offer so much more content, the other services - and thus, tablets that aren't iPads or Kindles - are pointless.
Is that assumption correct? Or more to the point, how can you tell?