If you want to build a rich user interface web application that
requires several state changes, spans multiple business processes and
requires complex data handling at the back-end and still want to give
the users a really rich and consistent experience (no refreshes!), then
do have a look at Flex as I believe that it is definitely a good
choice.
Refer Sandeep's blog to get a fair idea regarding flex and it's advantages. After that if you are ready to try your hands on it, have a look at my blog where I have explained this with an example.
