I used to have a 642 and now own a 649. The differance in weight as far as carrying doesn't seem very much to me but when it comes to recoil the steel 649 recoils with 110 gr. .357 loads no more than the alloy 642 did with 38 +p loads. To me being able to shot a more powerful cartridge with the same amount of control cancels out the weight advantage of the alloy gun.