From http://doc.exitgames.com/photon-server/
Photon Server vs Photon Cloud
Photon Server is an On Premise (OnPrem) server application that you can run and host on computers of your choice. Fully customizable and authoritative control gives you the freedom to configure and configure your own infrastructure for multi-user applications.
The Photon Cloud is software as a service (SaaS) and, as such, is a fully managed service. You can completely concentrate on the application client while hosting, server operations and scaling - all this will be taken care of in Photon Cloud.
Server Administration
Photon cloud
Zero server problem. Sit back and relax, and our experts will take care of the servers.
Photon server
You get full access to Photon for your applications. You start your own servers or rent suitable ones and make sure that they are available to your users. Photon magazines and performance counters provide all the information you need about poor performance and stability.
Scalability.
Photon cloud
The Photon Cloud scales automatically for all users. Using our SDKs, your client application is built for an efficient workload balancing workflow.
Photon server
Our load balancing is included in the source code. This is a solid foundation for scaling across multiple servers. For the correct number of servers for your clients lies your responsibility.
Licensing.
Photon cloud
Choose between different subscription models from indie development to corporate solutions, check out our different pricing models. Why don't you just give it a try? Photon Cloud comes with a free Plan of up to 20 CCU per app.
Photon server
Licenses are purchased through the store and are provided as downloads. Cheaper licenses limit the number of concurrent users per server. If desired, a corporate license is available for any number of servers upon request.
The logic of the game.
Photon cloud
All user logic runs on the application client to provide zero experience.
Photon server
Server logic can be fully configured in C #. Several predefined applications are available as a source and provide a high-performance infrastructure for your application. Take advantage of our protocols and abstracting low-level functions and add any function that you may not have noticed.
Get started instantly.
Photon cloud
Photon Cloud allows you to register and immediately launch the application. No configuration required. No server required.
Photon server
After downloading, run in less than 5 minutes. The photon is easily configured and launched locally as well as remotely.