Kendo UI is an HTML5, jQuery-based framework for building modern web apps. It is broken into core components. Kendo UI Core and it’s open source, and the other is called Kendo UI Professional it is commercial.
Pro Platform-based UI
Kendo knows what device it is being viewed on so it can adjust the UI accordingly. If a user is on a PC the user will see things differently than on a mobile device. Between iOS and Android the user will also notice a different as it pulls from the core UI of those core systems.
Con Expensive commercial tools [$699, $1,499]
The other core tools developed with Kendo are the commercial tools. There is the Professional version for $699 that will result in more jQuery UI widgets and client support. The $1499 "DevCraft" Complete edition gets developers the DevCraft .NET toolbox, testing and debugging frameworks and applications, as well as priority support.