I find k2's flat rock and hyperproressive sidecut really slow to react. It gives a stable ride and landings, but isn't eager to initiate a turn. Great for lazy boarding and crusing around. Btx is the opposite, quick turning, and with magne and a constant radius sidecut it carves really nice. It requires more attention since it is responsive. Both retail for the same price so I guess the price difference depends on the deal you can find.