This was because the company behind Ubuntu (Canonical) shut down the service, they didn't go under themselves.
If the cloud infrastrucure is Box's, and they cannot pay the maintenance fees anymore, I would start seriously worrying.
In a way, committing to a company whose main business is cloud storage gives you more guarantees they won't shut down the service out of the blue (since it's their only, or main, source of revenue), while committing to a big company with their eggs in more baskets (MS, Google) gives you more guarantees that if they shut down the service you'll be given some time to react.
If the cloud infrastrucure is Box's, and they cannot pay the maintenance fees anymore, I would start seriously worrying.
In a way, committing to a company whose main business is cloud storage gives you more guarantees they won't shut down the service out of the blue (since it's their only, or main, source of revenue), while committing to a big company with their eggs in more baskets (MS, Google) gives you more guarantees that if they shut down the service you'll be given some time to react.