if you wanna keep it in the family get the k2 formuals. They may have one of the best features for bindings... the hinged ankle strap. so that when you wanna strap back in the strap hanges away from the base so its clear for your foot to go in,
they have a decent amount of flex. its the preferred binding to match up with the www. I dont personally believe in the big hype of binding flex. any binding you put on there is going to work relatively the same... to prove it.. im riding the crrent auto evers on a nitro swindle as a strict park board. go with what you want. youll be fine.