Depending on your platforms of choice, iCloud Drive has been a great solution for me. I was an early Dropbox user who got out when they started limiting the num

Depending on your platforms of choice, iCloud Drive has been a great solution for me. I was an early Dropbox user who got out when they started limiting the number of syncing devices for free accounts a while back, and the $0.99 a month I pay to Apple for 50GB of storage in a folder that appears on all my devices works exactly like I want it to - I save stuff there, and then forget about it until I need it, and its magically on whatever device I'm using. Sync could be a feature, or sync could be a product. But the lesson seems to be that if your product is sync, and you grow big and take lots of outside money to do it, sync won't be your product for very long. You'll need to expand and try to do everything else that could use good sync as a feature.