Home Power Magazine, Jun./Jul. 2014, by Ian Woofenden & Roy Butler.
http://www.homepower.com/articles/wind-power/equipment-products/2014-wind-turbine-buyers-guide?v=print

"Without question, wind is a tough renewable energy resource to tap. The best wind resource is high above the ground, requiring tall towers. And it’s an unforgiving resource, pounding on the equipment, which needs to be robust and requires regular maintenance. Building machines that can be productive while withstanding the rigors of life at tower top is no easy task. Add to this that uneducated customers want to keep costs down, and we end up with unrealistic expectations and market pressure for lower-quality equipment. What’s a potential wind energy lover to do?"