I've heard they are quite decent but its basically a web browser (or was) so if you don't have the net where you are then you're pretty much fudged as everything is cloud based.
Most apps work offline in a limited sense, it's no mac/ultra book but for the price you get a decent enough machine which runs a great browser. I installed the chrome os on an old laptop a fre years ago and it's really come along since then, if the laptop wasn't so very, very slow I'd be able to use it for most of my browsing.
Most reviews have been very complimentary, best advice I've read is 'try using no other program but chrome and its apps for 24 hours, if you manage it then a chrome book is perfect for you'