2 months with the google CR-48 notebook
Above is the CR-48 running Ubuntu. I used a guide to dual boot the chromium OS and Ubuntu over a month ago, and it is nice to have both OSs on there. The notebook is not all that powerful, so performance in ubuntu is nothing spectacular, but the boot up is maybe 10 seconds and it is nice to have a bit more functionality when I need it. I mostly just stay in chromium though.
I have switched to the dev channel for the updates to the chromium OS. They come out weekly and sometimes more often. The regular channel is called beta, so the dev channel is bleeding edge. It has cut me a few times. Lots of bugs and twice it has made the OS completely useless. I am very fortunate to have gotten one of these and I gladly submit bugs and deal with it being unstable for a free laptop though.
I still use the heck out of this notebook. It boots up in just a few seconds and accomplishes 95% of what I use a computer for on a daily basis. When I need to burn discs, play portal, upload pics from my digicam, or mess with my phone I use the desktop. I am almost ready to turn off the desktop because it gets used less and less. I would love to take this thing on a vacation, it would work great. The included 3G would work great if I could not get a wifi signal. The battery lasts for a long time since it has good power saving and no spinning discs. Only complaints are that the rubber coating picks up oils from your hand something fierce and the lack of a mouse button makes it hard to highlight text.