I bought it for an excellent user environment for everything but programming, that could alt+tab into a programming environment. All of my non-tmux work is inside a browser. It made sense to me that I would have an environment that rapidly (less than 3 seconds) boots from cold to Chrome with optional Linux environment when I need it. It has advantages of being automatically encrypted and having deep integration with Google Apps that I use every day.

Thank you for your great answer . I am also considering buying Chromebook because my case is almost same as you (everything is inside of chrome or inside of bash ) , but I am a little skeptical about crouton , Do you have(or know) any video for showing/introducing how it works on Chromebook , how multiple tab's in bash works , I know this question is little wired but I haven't seen any crouton on chrome book yet , So I am very curious . Can it replace my ubuntu machine ? ( because I use it just for chrome(web) and heavy terminal usage (bash , gcc , gdb , emacs , etc), and I don't use any gtk qt etc app). Thank you .

They have some great docs at https://github.com/dnschneid/crouton and the community's great at http://www.reddit.com/r/crouton

As for replacing your ubuntu machine, the default distro is 12.04, but I'm sure you can install the latest.

I don't know about the amount of shell tabs you can have (as I use tmux), but my short experiment seems to hold up well.

The only problems I think you'll face is the scary 'OS Verification' at startup and limited memory (but can be solved by using a SD card). croutons are cheap to install so install, remove, install until you find your niche.

Oh , I think there is a misunderstanding going on here , Maybe I describe it in bad way , By replacing I didn't mean installing ubuntu on chromebook , I just want switch away from this whole gtk/qt/unity/gnome/kde/xfce/cinnamon/mate non-sense. Main thing I am looking for is how is crosh , when you using it in heavy way (gcc,emacs etc).

You can also install a chroot with the cli-extra target. This launches the chroot in a TTY with the `sudo startcli` command from the crosh shell. Instead of launching into a desktop environment.

Then I just startup a ssh server there. And head back to ChromeOS and SSH to local host (the secure shell plugin is good for this). This means my chroot is totally independent of any chromeos windows or crosh shells.

I run a window manager with a full-screen xterm that has my tmux session. My packages are installed in a chroot that uses either Ubuntu 14.04 or 14.10 (I don't remember exactly, on a different machine right now) using Crouton. This was better for me since I have a non-trivial xmodmaprc that I prefer.

Could be for the price.

Indeed, there was a firesale for the c720, 130$ was a catch.

Or to get a really cheap device with long battery life. I've thought about getting one for travelling, since it would be lighter than my Thinkpad and way less annoying if it got lost or stolen, but still has a keyboard and can run many "normal" linux applications.

I want the Chromebook because it's small, inexpensive, and fast for things like checking email. I want Crouton because it gives me Emacs, R, and anything else I want to run on Linux. I bought it in spite of the installed software.

I'm not trying to troll here..

What software? "The browser"? And do I misread the crouton instructions or is that actually still running the very same thing, same software, in developer mode with chroots for Other Things™?

You did not misread. Crouton runs alongside ChromeOS and you retain full ChromeOS functionality.

My laptop died and I am broke and jobless, and needed to do some programming for InstaSource. My only choice was to use my Chromebook. Now I do all my coding on it. It's surprisingly awesome!

Nope. I bought mine because it was a cheap experiment. If I couldn't use something like crouton I would have never bought it.