Out of all the Webtops I tried, the two standouts were Glide OS and G.ho.st. Both have the largest storage capacities, and they offer a wide variety of applications for work and play. If I had to choose between the two, I would work with Glide OS for now, since it has the fastest response time and the fewest problems. But I also like what I'm seeing from G.ho.st, and even though I found some irritating bugs in the beta version, I think it will be a great service once all the kinks are worked out.
For my tests I used a MacBook running Mozilla's Firefox Web browser, and I also tested a few of these services on a Windows machine to see if there were any differences. With the exception of iCloud, which was specifically designed for IE, I found few differences running the Webtops on Windows or on a Mac. This is a good sign since a Web-based system needs to be accessible from whatever operating system you happen to be using.
One of the most bothersome aspects of the Webtops I tested was their tendency for the browser to switch out of the Webtop environment and back to your regular browser. This happened most often when I was operating a Webtop in full screen mode, when there was little reason to escape the Webtop space for the standard browser environment.
Despite that complaint, Webtops are a great way to store files for which you need quick access. More importantly, Webtops can give you a familiar work environment that looks the same whether you're working at your home computer, or remotely from a borrowed or public computer. They won't be replacing your traditional desktop anytime soon, but Webtops--the ones that run smoothly and that offer a reasonably broad application set--can release you from the hassle of carrying your apps and data around on a laptop wherever you go.