Mark if you can afford it, I'de highly recommend going with an electrical system. Windwills are far to inconsistant honestly. Unless you have constant 5mph or greater wind where the windmill is going, don't do it. It's really as simple as that.
Couple of hot days in the summer with no breeze and your pond will restratify. Wind picks up and turns your pond over, perhaps killing all your fish. The risk isn't worth it in my opinion, unless of couse as I said earlier you have constant wind

Not to mention the windmills simply don't push anywhere near the same ammount of air as electric systems.
If access to electric is why you're considering this, it's helpful to know that electric systems can have the airline trenched out and ran quite a ways. I've heard the systems we sell can go upwards of 1/4 mile. Electrical usage is relativly minimal, 20-30 bucks extra a month.
Now for the good news, since you have a new pond you technically don't need an airation system. Oxygen issues generally start to arise in ponds with higher nutrient loads. Typically newer ponds don't have high nutrient loads, well, because they're new! You fish will benefit from the extra oxygen though.
Lastly, if you decide to go with membrane diffusers or stone diffuses there isn't much of a difference. The vast majority of of oxygen exchange is going to actually occur at the surface. The template on the bottom of the pond basically acts as an "elevator" moving oxygen poor water to the surface where it's exposed to the atmosphere and oxygen/gas exchange occurs. Also, windwill "templates" are generally a single stone, so they don't move much water in comparison to electric units. The same can be said about 2 template systems that Vertex manufactures. Our standard template is 4 air stones (for electrical systems) As a rule of thumb (for the most part

) more stones/membrane diffusers per template - more water will be moved.