I think I can add a few suggestions based off of recommendations that have been made to me over the years and personal experience. I agree a lot with what has already been said about tangental spoking. It would be interesting to know where you are experiencing the harshness. If the handlebars then you can concentrate in the areas of the bars, stem, tires, spoking and seat height. More often it is the saddle causing some discomfort that is described as a harsh ride. If so then try a different saddle, one size or type does not fit all so experiment. Saddle height is again a possibility as your hand to butt weight distribution can have an effect on comfort. I have a Land Shark bike that I love but the ride was a bit harsh and someone suggested that I use a carbon fiber seat post and guess what, it worked by dampening some of the road vibrations. Try and narrow down what really bothers you and attack it from that viewpoint. Would be interesting to see what you find out.
Ray Homiski
Elizabeh, NJ