Yeah, there is actually a difference between the two types. With a wing paddle, it's made is such a way to "grip" the water and pull you along. While with conventional paddles, it's more of a pushing the water along your boat. Pushing a pulling may sound remotely similiar, but when kayaking their is a large difference. I personally would not get a crank design. I would look into a two piece Aqua-bound carbon fiber shaft, with White abX resin blades. They run around $150 dollars. After a long day, the money is worth the price though. There is the all carbon fiber shaft, it's does weigh 3 ounces lighter, but it may run you about twice as much.

Paddle2gether