Actually, I have, and it's perfectly adequate if you're using a netbook as a netbook. (The biggest number of Windows complaints I see on the eeeuser.com forums involve people who have 64-bit driver problems, for example.)

I mean, if you're comparing running a Chrome browser under Windows 7 Starter with running the Chrome "OS" on top of Linux, it seems to me the biggest difference will be the option of persistent storage, not the polish of the user experience.

That said, I have two netbooks and both are dual-booting Windows 7 Starter and Ubuntu 10.10 desktop.