Everyone loves the Nexus 7. It's the "right size." It's "like butter." Even the Apple loyalists are questioning whether the broken nose syndrome that can come from precariously balancing a 10 inch 1.5 lb tablet on your chest late at night is worth it in the face of this little waif.
For me though, there is no clearer sign that the Nexus 7 (like the much crappier Kindle Fire before it) belongs to a new class of device: the disposable vending machine for digital content. Worth it from a software perspective only if you are ok consuming content from the hard wired app stores that each of the platform players provide. They give up the gross margin on the hardware and you give up: usability, control, and general purpose-ness for the sake of consuming content like you never have before.
Sure you can install Android Market (er, Google Play) apps. And sure you can even replace the launcher— if you are interested in getting back into the brain damage of the typical Android spring board experience. But this is not the experience of the mainstream user paying $200-250 for what seems like a "deal." And the deal? Paying for the placement of a vending machine right in your lap— one that sells you cokes while you can read up on your tweet stream.
As far as I am concerned, the main thing the Nexus 7 proves is that the e-reader form factor can be extended for checking email, playing games, and the occasional web surfing experience. But this is much more of a wake up call for Amazon (who hopes to own the category of e-readers++) than Apple who might be just fine waiting to launch a 7 inch tablet until price pressure forces them to.
I like my Nexus 7 (unlike my Kindle Fire). But primarily as an e-reader. As a vending machine, I prefer the kind where I stick quarters in...