Patrick, who has himself worked on Flex at Adobe, says that while Flex is great technology, it does have a "foundational dependency" on Flash Player, and this factor is forcing projects of all shapes and sizes to rearchitect towards HTML5. Suggesting that this disruption may in fact open up an opportunity for Flex developers to learn a new technology, Patrick asserts that Flex developers now have the chance to "define and lead the movement toward HTML5" application development. This is because they have, "Years of experience building world-class applications with components, classes, MVC, and a futuristic version of ECMAScript."
Both the Flex and Sencha frameworks are object-oriented and component-based. Both offer a range of UI widgets, layouts and animations, with object lifecycle management and event handling. Both have tools aligned towards the needs of rapid application development, but of course Sencha is keen to promote the use of its "Designer" visual app builder, which is typically positioned as a route to building more complex user interfaces, data models, and controllers.
For more rapid development, Flex developers can use Sencha Designer, a visual application builder for creating complex user interfaces, data models, and controllers. Sencha toolsets and frameworks also are backed by the company's technical support, services, and training.
Sencha's Patrick concludes by saying, "The developer paradigms of Sencha and Flex are very similar and developers who know Flex will learn Sencha frameworks quickly and find their existing knowledge of component development instantly valuable. While the syntax and architecture are different, I keep finding patterns and concepts that match Flex perfectly but are suited to the interpreted model of web development and deployment."