Maybe neither one
With the 640 you get excellent no fuss CCW, but only DA pull. With the 60 you get a SA option for accurate plinking(yes, it can be accurate) and also a CCW capability, but less so due to some chance of the hammer snagging on a draw. I have both to cover all bases. Otherwise, the Bodyguard is the best of both, no snag, and you can cock the hammer for accuracy if you want. That is why they are hard to find right now. Except for some well worn lightweights I have seen at shows. Check them as an option- I would love a stainless steel frame Bodyguard if such a thing exists.