This depends a lot on the feel you are looking for. The Five standard gets a one piece highback and a nylon base. It is noticably more flexy than the Five SE (or the M9) which gets an aluminum heelcup from the mod-back. The top panel on the mod back is very flexible but on the whole it is still more of a power binding than the Five due to the aluminum usage. The Five SE and the M9 are very similar with the differences being the flex in the top panel and the design of the surf strap.
what should i care the most on the flex on a binder; baseplate or highback?
which is more important in forgivin?