Ranked in these QuestionsQuestion Ranking
Pro Free Core tools
Kendo UI is separated into a commercial and open source frameworks. The core of Kendo UI is in the open source frameworks, but some usability and benefits of Kendo UI are lost without the commercial version.
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.
Pro Theme Builder
An interactive tool that has been created to customize an apps theme. Users are able to select from many pre-defined themes, edit them, and download the theme to bring into a project.
Pro Great developer tools debug/hotreload/analyser
Pro Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers.
Pro Open source
Pro A single codebase for iOS AND Android
The developer's goal is to allow people to make apps running at 120 FPS.
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.
Con Still in development
According to the website, Flutter is still in its early stages of development.
Con Based on Dart language
Dart is a Java like language, easy to learn and startup fast for millions of Java developers. BUT if you have to learn it ... it's a con.
Con Dart is unpopular and never gained serious community traction like Kotlin or Java
Con Does not support 32-bit iOS devices
If you plan on targeting iPhone 5, 5C or earlier, you can forget about Flutter.