What happened? Google decided to stop fighting the desktop metaphor. Early Chromebooks, like Google's CR-48 and the first generation Samsung and Acer devices, were about as much fun to use as an airport computing kiosk set up to support Web browsing and nothing more. Chrome OS felt like a prison, like the desktop typically behind the browser had been hidden. That may have been nothing more than user expectation, but user expectation is part of the user experience, and that experience tends not to be positive when expectation is denied.
Earlier this year, Google made its Chrome OS browser window behave like a browser on a Mac or Windows computer--it can now be minimized to reveal a desktop with files and icons. Chrome OS has gained a menu bar at the bottom of the screen with Web app icons. Clicking on a device-related icon, like the battery, produces a free-floating menu pane, without any reference to the Chrome browser. There's a files folder, accessible from the Apps menu in the menu bar, that displays local downloads and remote Google Drive files. In other words, Chromebooks have adopted more legacy user interface conventions and are better for it.
Another huge improvement is the ability to work offline in Google Docs and other Web apps that support offline storage APIs. Google still lives in the fantasy world of its self-interest that assumes Internet connectivity is the norm--its offline documentation still talks about the absence of connectivity as a rare thing. But at least the company has accepted that people don't always have Internet access and has updated its software accordingly.
Google's Chrome Remote Desktop software, available from the Chrome Web Store, enhances Chrome OS even further. It allows users to easily access OS X or Windows computers through their Chromebook or any Chrome browser. And that's to say nothing of the value of Google's cloud-based services, like Google Apps, Google Drive, and Google+ Hangouts, which run in any modern browser, on devices running Chrome OS, Android, OS X, iOS, Linux, or Windows.
Google calls the Samsung Chromebook "the perfect additional computer. For everyone." It's not perfect, but it's very good, even excellent compared to what else you can get for $249. It would make a fine additional computer, if you need a second or third, or if you need a device for traveling abroad but don't want to risk the loss or theft of the data on your laptop. It's also well-suited for teens and tweens, or anyone disinclined to enjoy computer maintenance and security-related twiddling. It's a viable alternative to a tablet, particularly if you do a lot of typing. It's not a replacement for high-end laptops. But Chrome OS keeps getting better, and Chromebook hardware is headed in the same direction.