Sharing at the folder and file level is a snap, including sending stuff to non-Windows and non-SkyDrive users. With Dropbox, I tend to use the desktop application much more than the Web interface, unless I'm traveling. Not surprisingly, SkyDrive's desktop app is pretty much the same thing--the familiar Windows Explorer file-and-folder system. They're identical, right down to the tiny green "check" icon that lets you know a file is synced. The installation was simple and fast, as it should be.