Huh . That a rather , ah , unique binary choice, unless you just happen to have a case of each on hand.
Strictly on the asked question , I would probably select the .357 Crit Duty, but : 1. At one level it comes down to what you can confortably / effectivly control with your gun in your hands. Unless I'm having a prematurely senior moment , a M627 is a normal N Frame in stainless. Recoil will be much less a factor than in the smaller snubs that are usually inquired about in this regard.
2. There's a cpl dozen defensive rounds that would come to mind before either. ( Not that I wish to get shot with either , yada yade ).
IF you were wishing .38+P level performance ( yes the 147 +P+ is mild in vel similar to most +P's ) , the two top choices are old school , but still top performer 158 LHP , or 135 Gold Dot . I'm also know to use CorBon 110jhp +P , but it's a matter of taste and philosophy.
.357 loads , it really depends of what level of recoil and blast suits your preference. And wether defense against two legged felons , or small bears and large angry livestock run amok. (Any major brand) full power 125jhp will be very effective . And have signifigent sound , fire , and recoil. Medimum velocity 125 and 110jhp will have similar recoil. I haven't check to spec sheets this week who's offering what in a medimum 125 , but the Golden Sabre is one such. Some people feel the 110jhp UNDERpenetrates . A matter of taste , but no overpenetration worries. And WWB 110 is cheap enough in the 50rd boxes to actually shoot a meaningful amount in practice.
And I suppose the Crit Duty/ Defense is well enough made , but CorBon PowerBall has been my preference for that niche since before CD was a gleam in Horndy's eye, and never saw a reason to switch.