I currently use tablet mode for 2-3 hour session for portrait reading (Wikipedia Android app, long-form articles) and from time-to-time light note-taking (Squid Android app) and PDFs. Haven't used crouton or done dev work on this Chromebook yet.
Here's a quick review of modern touch-screen Chromebooks used as tablets. While the hardware is exceptional, the software is terrible in tablet-mode. Here are the painful issues that I can currently remember:
1. Easy to accidentally close the entire browser by brushing the X button (I was thinking the browser was crashing the first 4-5 times it happened, very frustrating as can't CTRL-SHIFT-T in tablet mode)
2. Easy to accidentally close a single tab for the same reason. On an Android devices there's a little undo popup to reopen tabs, but that kind of obvious touchscreen user-interface polish isn't there on ChromeOS yet
3. Two finger touchpad scroll doesn't work on Android apps for scrolling -- painful as heck when Wikipedia links open in the Android app in laptop mode
Side note: I wish there was a good app to non-destructively markup PDF files with the stylus. I think it was at WWDC this year, Apple showed great work in this area, but sad not to have found software that appears as good for Chromebooks/Android yet.
I know Google engineers will come across this post, so hopefully these pain points can be fixed eventually. Chromebook hardware is so good (and cheap), but there's a few painful areas still.