From David Pogue in the NYT, once you get past the discussion of e-readers:
But Android tablets’ plastic backs feel cheaper than the iPad’s metal. Their cameras aren’t as good as the iPad’s. Their batteries generally don’t last as long.
Above all, the Android-tablet app catalog is still very disappointing. The apps that exist are often hastily rejiggered versions of Android phone apps, rather than apps thoughtfully designed for the bigger screen. For example, the Android apps for Twitter, Yelp, Pandora, Vimeo, eBay, Spotify, Rdio, Dropbox, LinkedIn, and TripAdvisor are scaled-up Android phone apps — basically, they’re just lists. On the iPad, the screen is filled with useful visual information about whatever is selected.
No matter how much progress Android tablets make in hardware and price, those 275,000 tablet-designed apps can’t help making the iPad more attractive.
I guess Microsoft Surface wasn’t even deemed worthy of discussion.