If your system depends on the Web always being available, then you're going to have times when you can't do anything because you can't access your data. When the Web isn't there, your data does not exist.

I'm usually an early adopter, but I had some severe problems with the 'Cloud' very soon after I stated using it. I then went the other way, making it my policy to store as little as possible on the Web. My mail is still stored on the Web, but if I could work out how to easily back that up or store it totally locally, I would.