Because it works, it works reliably, and it does so on all of my devices. That isn't the case with most of the competition that I've seen or tried. I find the

Because it works, it works reliably, and it does so on all of my devices. That isn't the case with most of the competition that I've seen or tried. I find the interface (both local and web) to be much nicer with DropBox as well, especially over things like Drive. The price differences are relatively small, and I have no use for the Office suite.