Marco Arment developer of Tumblr, founder of Instapaper:
Because when normal people — not gadget bloggers and geeks like us — need to consider an alternative to the iPad, they’re not just thinking of Apple’s lack of “openness” (as Google so vaguely and poorly defines it in relation to Android) or the iPad’s lack of some individual hardware feature. Buying an alternative means giving up Apple’s entire ecosystem. That’s worth it to some buyers, but it’s incredibly impractical for many.
A successful mass-market iPad competitor needs to be so good that people will ignore all of that, buy it in large quantities, and let it develop its own entire ecosystem.