It's not only an awesome technical achievement, but it has also so much potential to be useful. And yet, something at the back on my head is screaming: WARNING! I have the intuition that, on the long run, using more and more tools that are not on your own machine will create a dependency on systems big companies control. And something tells me we are going to pay for it in the end. So I'll stay away. Maybe I'm gettin…
My experience? Chromebook / Crouton, usually offline with occasional network access. I ended up leaning hard towards SPA's + javascript, with most of the documentation being "legit" available. (JS, HTML, CSS, DOM, etc.) ...occasionally researching + pulling in libraries on occasion.