what do you think of storing your wallet backup in the cloud? like a storage service. like google drive / drop box / iCloud drive / etc...?
of course there is the USB stick and paper option too...
also how do you load a backup into bitcoin-qt?
definitely :
NO.
dont trust any cloud service to store sensitives datas.

As long as you encrypt it before uploading, it doesn't matter. You could even backup the data by publicly posting it on facebook and twitter for all you care. Encrypted means nobody can read it, no matter how or where you store it.