Let's start with the negatives; if you are a power user who wants a computer for heavy document creation, video editing, photo manipulation, music making and things like this then this is not an option as a main machine.
The app environment has a distinct advantage in terms of keeping things neat and safe, but it comes at the cost of true openness and until programmers find ways to pare down their products so they run in a browser (which is by no means out of the bounds of possibility) Chrome OS is simply not going to cut it for many as their main computer.
But the times they are a-changing – and for millions of people the browser is their main focus, and for millions more the option of having a cheap secondary option that is all about the internet will appeal, and it is these groups that Google appears to be targeting.
Google's Chrome Web Store can definitely be filed under the tag "burgeoning." Although it's certainly not got everything you might want (no official Spotify app, no Photoshop, no Microsoft products like Live) it's certainly got plenty to keep you occupied.
There's no disguising the fact that, until Chrome OS hits tipping point, developers may well not be focusing their efforts on converting their legacy programs for the operating systems.