[mtogo]

It's not an iPad-with-a-keyboard. The iPad is much more powerful; it can actually run client-side apps so you can do things either offline, or without the slow, bloated feel you get from web apps. You can SSH from it with reasonable speed (unlike ajax terminals). You can take a picture and save it locally. The list goes on. It's a polished system that's been around for a while, and it's supported by a company with a history of actually supporting and caring about their products.

The chromebook is more of a cut-down web browser with a keyboard that you can't use without having a google account and forfeiting your privacy.