How to choose a variety of alfalfa

Ok, I'm going to plant my first stand ever of alfalfa in a couple weeks and I'm trying to decide on a variety and it seems as though there are many different traits to choose from compared to grass and it is a bit confusing. It is not as simple as seeing what others in my are are planting because there is nobody else growing alfalfa in this area. I know I want a variety that is leafhopper resistant and the county extension office said that a fall dormancy of 5 or 6 should be good. Is there any other traits or pest resistance that I would want? What about a branch rooted variety? Thanks, Hayden