Another option, that's free, is your own PC. Why pay for exotic solutions to simple problems?
I use a program called GSyncit (it's paid) that synch's Outloook to my PC, I have a manual backup of all my music on my PC, and photo's can be easily copied to your PC. The connection to your PC is going to be faster, and arguably most importantly, there are no strange TOS issues with my PC. Who knows if the cloud your using will be hacked, or crash or have other issues. As my phone is connected to my PC every night to charge anyway, it's easy to make periodic backups.
The likelihood of both my PC and Phone dying at the same moment is very slim, and even with that, my phone data is duplicated on two different drives.
'Tis better to be silent and be thought a fool, than to speak and remove all doubt. - Abraham Lincoln