Not just down a round on the 640 Pro, but a noticeably inferior trigger compared to the K6S at nearly identical weight.
I say this as a 640 Pro owner, too; I still think it's the best conceived S&W defense J ever, but the Kimber is better in every way, unless low weight is the primary requirement in which case the 640 is out anyway. I said it before in this thread and I'll say it again: the K6S is the personal defense revolver S&W should have built, and I'll add that now it's the revolver S&W should learn from and beat, but I'm skeptical.