What are your expections?
A few things that I found interesting: you can only run web applications, as they've limited the ability to write to the disc drive (it seems they've limited this to SSD), the source is open, data is encrypted, no app store in the foreseeable future.
So my question is, how is this different from a good web browser? Actually it is different, you can't run your native applications and have to rely on the varied "web applications". Google needs to spend more time improving their browser instead of taking on a full fledged (gimped) OS.
And i think Chrome browser is one of the most powerful on the market so how do they need to keep working on it?
I like the idea of the OS but I know it could only be on a netbook for me. I do tons of design work and I have to have Photoshop, Indesign, AutoCAD, Revit, Sketchup, etc all running...at the same time...and fast. Chrome OS can't do that. I would LOVE to have it on a netbook (Eee PC 1201n, please) so that I can do my internet related things as well as document creation and such but it would be completely limited to a secondary machine because I need to have all those full fledged apps at the ready.
I would almost rather have this as a secondary OS on my machine. Hopefully that way I could boot into it quickly and save battery for when I'm on the go.
What you also have to consider is if this is freely available for people and is Linux based, it will most likely have driver related issues for most, which is probably the number one reason why hardware manufacturers have not embraced Linux based OS's the same way they have Microsoft's, so from a support perspective this isn't optimal.
There is always room for improvement for anything. Chrome is a great browser, but it still has some nagging issues which keep it from being my sole browser, offline support is one of them (gears is still not quite there yet), theming and extensions support.
What I will say though is that this has the best chance of putting Linux into the masses and to makes cloud computing on a netbook ever more enticing.
Some sort of a Chrome OS plugin or Wine would not cut it since I need all the horsepower I can get behind these apps. The concept of that is flawed because Google won't let you install anything with Chrome OS so a Wine Web App would be pointless because you can't just install something to the internet. Developers would have to rewrite their applications as web apps. Some of the more basic apps can do this just fine (see MS Office) but the more advanced ones like Photoshop are already seriously gimped when you're trying to use them on an internet connection.