The current state of the Chrome browser on Linux would make this "web OS" the equivalent of Windows 3.11. In it's current state, there is really no way to compare Chrome and Chromium and claim they represent the same kind of polished product. Chromium had so much issues with stability and performance, that I had to give up on it. I took a short detour by Opera, before Firefox 3.5 became usable, and I was back where I started.

If I were going to make a web OS, even for netbooks, I would rather have it use Firefox 3.5 as performance is much more predictable and reliable, not to mention it can be extended with addons, something I would consider a minimum for any platform.