i know its mainly about your personal preference, but I would like peoples opinions. I already have a 9mm Sigma, and Im kinda leaning towards the 9mm SD. Is there that much of a difference between the sigma and sd to get another 9mm? My main concern is I dont want to buy another 9mm thats basically another sigma. If thats the case then Ill go with the 40sd. Any help/opinions is greatly appreciated.