Complete browser portability: any browser that supports flash player and that includes almost every browser.
Strong backend connectivity: from its inception, flex has featured excellent support for popular backend technologies such as the java and dot Net.
Streaming: flex offers excellent support for streaming binary data. Heavy allocations that needs to transfer large amount of data to the end user.
Asynchronous: Asynchronous request/response model. Flex offers complete support for asynchronous processing of user requests.
SVGs (Scalable VECTORGRAPHICS): flex stands out from most other RIA-based technologies because it supports vector-based drawing and direct embedding of SVG mark-up files. SVG based images LOOK equally good at any resolution a given browser supports.
Security and Rich User Interfaces: Robust security flex leverages the highly tested flash player security.
RUI, flex benefits from halo skins, gradient FILLS, vector graphics and other flash player features