I'm a SRE at a large (non-Google) tech company, and I have a Chromebook Pixel as a secondary system I use all the time, at work and at home. It's incredibly useful and I'm quite happy with it (with ChromeOS in developer mode, which just gives me a shell that's occasionally useful). The idea of high-end Chromebooks makes a lot of sense (for some people) even though I couldn't've guessed it would before I had one. Still, right now to me "Pro" is just a word. It's unclear to me how it'd be different from what I already have.