I would say that most people prefer calm conditions because they have better control of the plane. (Then again some people do like the wind).I prefer calm conditions for the simple reason it makes hovering easier. You can see how the plane acts in a hover and get a feel for the controls. Wind however can also be helpful in some maneuvers like harriers. As long as the wind isn't crazy and more of a constant breeze all these 3d maneuvers can be done. Weather you have wind or not it all comes easier with practice.