The short answer is that a Private cloud is part of your Internal Network and a Public Cloud is part of an External Network. Why choose one over the other? If you want to control every aspect of your resources, including the data, or you already have a large data center, a Private Cloud is your best option. The biggest downside is that you are responsible for the upkeep of the space, hardware, cooling, power, and personnel to ensure that it all stays running. In the long run, even if you do already have the available space and equipment, you will eventually be paying a lot more for a private cloud, but you do maintain full control/access to all equipment and data.If your goal is to save money, and not worry about updating most of your equipment, then a Public Cloud is your best option. With a Public Cloud the management of the equipment and parts of the software, depending on what type of Public Cloud solution you choose to deploy is the responsibility of the Public Cloud Service Provider (CSP). Saving you money on personnel, space, and equipment while still giving you access to the same resources at similar, if not greater speeds than you are already used to.