I finished my GP, gave it a wax job and took it along with the Expedition to the water and gave it a try. This was the first time I've ever paddled with a stick and I'd have to say that I was very impressed. I had been a little concerned about the amount of flex in the paddle, but that turned out to be nothing to worry about. In fact, what little flex actually happens, might be a plus; it gives a little kick at the end of the stroke.
I found paddling with the GP encourages torso rotation and a few other things that relate to what I've come to think is proper form. I settled on just a little less than 1 1/2" for the diameter of the shaft. It does increase the weight a little, but I think it is worth it for the more relaxed grip.
The paddle seemed to work great at every angle, except for maybe extreme high angle (verticle), because of drips. This might be fine for keeping one cool on a hot day, but I normally don't go verticle except on a banzai charge. At lesser angles the drips were of little consequence.
The first couple of strokes from a standing start are not as effective as a euro blade, but once you're moving, any disadvantage disappears.
I guess I should have moderated my enthusiasm for the new blade, because I overdid it a little. The tide was running right, so I went with it and decided to do a 25 miler (round trip). The whole trip went very well until I got back to the launch site and got out of the boat. I then realized I was completely out of gas. It took every ounce I had left to carry the boat to the trailer and drive home.