@amanda.hinchman-dominguez in short, JPRO projects the app much like a remote desktop and uses much more server resources to host application instances. However, it conveniently projects to a web browser like FireFox or Chrome without any plugins.
Graviton will run the app locally on the client's machine, but streamline the delivery of the app on-demand. It will use a proprietary non-web browser, and likely be a leaner solution.