CloudOn lacks some key Word tools, such as support for comments and footnotes. Also, you can't enable or disable Track Changes. However, if you're working with a file that already has Track Changes turned on, your edits are tracked and you can still see changes others have made.
CloudOn and Word are by no means your only options for document editing on iPad, of course. Apple's Pages does a good job, but for various reasons it's never become my go-to app.
Back to that original question: Which app should you use for document creation and editing on an iPad, CloudOn or Word? CloudOn is an excellent app, and it incorporates touch features better than Word. However, because Word no longer requires an Office 365 subscription and supports Dropbox, and because CloudOn makes you pay for some standard Word features, Microsoft gets my vote.
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