I second what Jay said. I use a Lendal with Nordkapp blades ... cupped slightly in both directions with a center ridge on the power face. It's a good blade for regular strokes, power strokes and bracing ... but it's not fun to use for sculls, slicing strokes or rolling. In my experience I've found blades that are slightly cupped in the lengthwise direction but otherwise flat with no ridges the most friendly overall. Love my ancient Lightning paddle for that reason.

Ken Blanton