better for what ?
Fdt is a editor, and flex ... a bit more.
FDT is currently the best editor for as2 (and soon as3) Flex is a framework. Maybe you think about Flex builder, wich is an editor for flex, but still, fdt has nothing to do to this, cause it still does not support as3 and mxml.
__________________ pebkac - problem exists between keyboard and chair