There seem to be about three stages of these that Empirical Audio has gone through. I've been looking to purchase one and have found a couple on various sites, but the price ranges are all over there place. The newest one's obviously costing the most. Is there a huge difference between the generations? Can anyone explain the differences in technology between each generation, or at least what audible improvements they hear? I'm not saying that there aren't any, I'm just curious as to what they are. 
