I haven't seen the scores, but I think the GFS has been generally good the last couple years. It hasn't really showed much in the way of any digital blue...which would be accurate. I actually use the GFS now up until within 24 hrs. Whether that's the correct way or not, I don't know, but I've seen the NAM miss enough times close to gametime that I find it more useful for showing potential convection than a broad brush of temps/precip.