The vendor you are working with should be able to share with you data about any historical outages in their systems, and how often the system is working at 100%. There may be a very minimal lag with accessing your digital assets via the cloud that you wouldn’t currently see with assets stored on your on-site servers.
This lag is due to the data having to transfer over the internet to get to you; and the speed of your internet connection will determine how much that will affect your team.