One more thing to keep in mind is privacy: While you mostly have control over your locally stored data, you cannot say the same for Cloud services. For storing personal/sensitive information to the Cloud, you should always consider encryption.
A third option is to have your app creating backups on your sd card, and use another app (e.g. FolderSync) automatically sync the backup directory to your local computer (or NAS device). This way you are a bit safer if your card breaks, and have more privacy. And you have both, a local and a remote backup -- plus even if you need the latter one, download is a bit faster as from the Cloud. If you trust some Cloud service, chances are also good that service is supported by FolderSync as well.