How can I sync data, photos, music and apps across multiple devices?

Hi! My boss has two desktop PC’s, a Mac laptop, a Dell lapop and two iPhones. He wants to have his photos, music, and documents accessible where ever he is. And, he wants it all automated. Obviously this is a cloud solution. I have looked at iCloud and some others, but have yet to find the “one ring that rules them all.” For example, with 20,000 photos to deal with, iCloud only deals with the 1000 most recent images. A human element needs to be introduced. Is there any solution out there that could solve this problem? It doesn’t need to be free. Thanks!