The real issue here is the difference in weight and the suitability for CC. As others have said, the 640 can be carried, with a little possible inconvenience because it is heavier. I don't own a lightweight, but have fired them. The 640 is much easier to shoot, and I have not found +P uncomfortable, nor have I found the .357 Golden Saber particularly daunting (although I would not choose a long range session with .357 cartridges). If you want to shoot +P or above, the 640 is the logical choice, and from what I have read, it will go on forever. It is probably best carried on a belt, but that is not a big issue for me. I have found it to have outstanding accuracy at ranges from 10 to 35 yards. My best groups seem to have been with Hornaday 125 gr. cartridges. I can't say enough good things about it.