Discussing turbine weight might seem a little odd. Why would a buyer care how heavy it is as long as it will go up into the air and generates electricity? Well, the average buyer may not really care but you are not the average buyer since you are diving into what makes a turbine tick.
In the case of a turbine, more weight may not automatically mean increased reliability. It is just another one of the important issues to keep in mind as you are shopping for a turbine.