By far most of the views are related to the admin area, which will remain the same. Only the client area has been updated to responsive bootstrap, and it's done. Yes, it was a fair amount of work but it was worth it.
Ha! You got me. What Mike said.
I've honestly not used it enough yet to say, Paul. But definitely will be. Sounds like it will be a default plugin one day though.
The client area was a bit of a pain to integrate to bootstrap. It's not just the templates/styles that change, it's all of the javascript that make DOM changes, how partial views are abstracted, modules/gateways/plugins, how module form fields are rendered, etc. I can only imagine the time necessary to convert the admin area to bootstrap.
You could make a plugin to do the custom code and it would save worrying over updates. 3.1 is amazing and 3.2 is fantastic from what I've seen. Bootstrap 3.2. Click a core number link and see what you'll be missing out on.