I needed a small laptop that I could carry and use in meetings, take notes and have enough battery to last all day. All I really needed was internet browsing, email and a word processing program. The ASUS Flip nailed it. I was looking at budget Windows laptops but a friend suggested a chromebook and I researched them. When I read about Chrome OS a few years ago, I considered it a joke of an OS and could never have seen myself buying a Chromebook. But with the development of web-based services and software, there is little you cannot do online now - I think Google really saw the future with this concept. After testing the windows laptops at my local Best Buy, I found the lower end machines (<$300) slow - even typing with all other programs closed, there was constantly a small lag in typing that I found annoying and gave me little faith they would preform better in other software. I tried the Chromebooks and found no lag - just a fast, responsive system, so I bought it. After several weeks, I have no regrets. The Chrome OS performs fantastically and Android app capability means a giant expansion of options and versatility.
Caveats: There are some negatives, both on the OS side and the hardware side. To me, all of these are minor, but importance will depend on what you are looking for your machine to do.
You need to be ready to learn: Grasping the concept that the 'desktop' was really my browser, not the background, took some time for me. 95% of things open a Chrome Browser window. Its a new OS, so its going to take some research online at times.
Android functionality is still Beta: The OS has 3 options, from most stable to least: Standard, Beta and Developer. When I bought it, Android was in the unstable Developer stage. I switched to that 'channel'. It was usable, but quirky and android apps would close on their own sometimes when switching and minimizing. Its now in Beta and is much more stable, but still not 'refined'. Google is throwing out an update a week or so right now, so its getting better, but I wish Google would give a change log. I find myself searching in the Google forums or using trial and error to figure out what they changed on the Android interface with each update.
Android is a bit slow: I have found some slow graphics or stutters in android apps, only. Since the hardware is as good or better than most tablets, I think the issue is more the optimization of the code or however they have Android sandboxed. Therefore, it works great for text and images, but your android games are going to see some lags.
You need to use gmail: I had a gmail account, but it was not my primary email. Virtually all email is browser accessable now, but since Chrome uses Google drive for its integrated storage, attaching a file to a non-gmail account is not easy or intuitive (although in gmail, its as easy as attaching any file). If you use dropbox or some other cloud storage, that can be used by downloading an interface program for your google drive. Basically, you add the interface software a bit like you add a network folder.
Final word: In the end, like any purchase, you need to know what you want and intend to use the machine for. This is exactly what I needed and Chrome OS & ASUS exceeded my expectations.