I've been watching
I should have known better.
Recently Paul Thurrott wrote one of his "What I Use" articles on cloud storage. Thurrott is the guy who started SuperSite for Windows and hosts Windows Weekly. For Pete's sake, this guy uses a Windows phone!
Here's what he said about OneDrive:
So why even bother with Dropbox?
Simple. It works. It works really well. It works quickly. And it works reliably.
OneDrive, meanwhile, is a mess. It’s slow and its unreliable...Admittedly I haven't given OneDrive a try. I have been a little gun shy given my experiences with other Microsoft file sync products.
I'll stick with Dropbox.