The problem with a NAS solution, in my opinion, is that it is local. Don't get me wrong: I have, and love, a NAS and use it to directly serve music to my playback system as well as getting a little redundancy in case a drive dies. If the house burns down, or floods, or whatever, though, I will lose my main drives AND my NAS. For me, that is the reason for a cloud backup. It can get expensive, so I guess it depends a little on what you want to achieve. Backup? Distribution? Both? And how many TB are we talking about?