It depends on what you like, how you ski, and where you ski. For powder only where you don't think you'll get into ice, tracked up stuff, or wind-affected snow a softer ski is usually best. If you're dealing with variable snow densities, depths, etc a stiffer ski is usually better. But it really all depends on what you like in a ski. Just remember softer skis tend to float better but chatter easily, and stiff skis will plow through weird/bumpy snow and hold an edge better at the cost of some floatation. That's why we have powder skis ranging in flex from the Pontoon to 194 Squad--"powder ski" is a highly subjective term.