The triple front will probably shift a little better. The triple has closer together more evenly spaced gears that are sometimes more convenient. If you really want to do this for weight considerations go to the Shimano website first, get the average weights of the different parts, add them up and see where you are. Then decide. It may be not as much of a difference as you think. You will lose you lowest gears. If you want to compensate by using a larger casette the weight starts going back to were you were.