Using their 4Shared Desktop (Windows, Linux, Mac) you can Sync folders between as many computers as you need. Now that Microsoft has announced that Live Mesh Beta is going away (March 2011) and its replacement is not available for Windows XP, this is a definite alternative that works great and gives you more space.
The 30 second wait for downloads is for downloading from shared folders only. If you're logged into your own account there is no waiting. In addition, if you like toolbars they offer one that ties you directly to your account.
Bottom line: more space than Live Mesh, Sync, and sharing files/folders make this a viable alternative to Windows Live Mesh that's worth a closer look.