Cloud-sycning MS Office documents on OS X/iOS
Mobile Documents folder

Actually, iCloud can be used to sync anything that you wish, including MS Office docs.

In ~/Library/Mobile Documents create a folder (call it anything you wish) and put whatever Office documents you like in there. That folder will sync with other Macs (and jailbroken iOS devices, and on the web too if you have a Apple Developer licence).

Dropbox

Alternatively, Dropbox allows you to sync files that you put in your Dropbox folder with anything (Macs, iOS &amp; Android devices using the Dropbox app or another app with Dropbox integration, and web).