On a whim, I bought an ASUS Chromebook C300MA-DB01. I wanted to see if it could work as a secondary work computer. I don't have a laptop at work, and I'm not comfortable with leaving my Macbook Air there all the time.
I fully expected to be a little disappointed with the performance and screen quality. I also expected to be annoyed by the simplistic browser based OS. Wow! was I wrong. If you are ok with storing things in the cloud, and using Google services, then this might be a perfect second device. While on my work network, I can ssh into my main computer, I can remotely edit code, and I can test websites with chromes developer tools. All of my Chrome bookmarks and extensions were there the moment I logged in, and there's a good selection of apps on the app store.
The only problem I have had so far, is with getting my work VPN connection setup correct. The Chrome OS needs to provide easier setup for VPN configuration. However, based on information other Chromebook users have compiled, I should be able to get VPN working correctly. It's just not a simple configuration. If I use it mainly at work, I won't really need the VPN to work.
I could easily suggest this as a secondary cheap alternative to a table or laptop for my Developer friends. Some of the newer models even have better screens. But, don't expect something this cheap to blow you away with build quality.
I can easily suggest a Chromebook as a primary device for family members or normal people that do not require special software or graphics heavy games. Most people do not need more than this. And it's more secure and easier to use than Windows or Mac OSX.