Boss,These are not concurrent technologies, but they complement each
other. The most usual option to represent the UI is Flex, which offers
many compoments to interact with end user and to lead him to a new rich
experience.When you say Adobe Forms you mean forms inside a PDF, right?
There is two technologies to implement forms inside PDFs: AcroForms and
XFA based forms.Well, from here let us know what are your doubts.Diego