Flash is better in many things compared to flex.
In flash we can do any kind of 2d animation and designs how we wanted
In flex all are default effects,we can only use them only,we can make good effects in flash however we want,slideshow etc,,and can create own skins,Game designing etc,
whatever u do in flash is not possible to do in flex.
yep.. I do agree with you.
However, Flash was originally developed and used as medium to integrate animation, sound and video. Even, it’s intended for online presentation with some interactivity.
And, Flex would be a better choice because
Flex development brings a new level of user interface to your website with rich, interactive web applications. Flex gives you the best applications by using graphics, animation and audio done in flash that can be viewed in any browser with the flash player installed.
Flex is the approaching technology for creating responsive, dynamic and visually prominent user-interfaces and more standard than Flash to develop Rich Internet Applications (RIAs). So first of all we need to decide our what kind of project it will be and choose technology as per your project requirements.