ewest's comment about visibility and being able to stand up in the boat is on the money.
Canoes are great, but they are not stable. I've had some late night unintentional swims in my pond due to the other person in the canoe leaning over too much; although he still insists that Navy Seal Team 6 was doing manuevers and sabotaged our late night canoe ride.
There was a Hank Parker show where he and his kid were using a type of kayak that had pedals for propulsion. This thing would go in just inches of water.
