Will fast growers produce well?

This sort of growth usually occurs when a plant is not getting enough light intensity. They stretch and grow very lanky so as to receive more light. Genetics can play a part, with Sativas being longer and more stretched out than Indicas, which generally stay smaller and more "squat" and with close internodes. Flowers on plants like this one usually stay around the nodes and never form entire branches filled with flowers, however, there are some Sativas that will flower the whole length of the branch with the internode distance that your plant has, however those flowers are usually very light/airy/fluffy and not very dense at all. Apart from increasing the light intensity, there is little you can do to change this plants morphology. Hope this helps,... Organoman.