You're going with a four inch barrel, so likely you won't be going for many fire-breathin' loads. As such, maybe some double action shooting is on your agenda, using .44 Special velocity ammunition?
If so, the Smith has a much better DA action than the Ruger, and to me, is more sitable to DA work.
Not sure of the 629, but my Model 29s all had the wide target trigger. If this is true for the 629, maybe consider a narrower smooth combat trigger.
Maybe you might better be advised to go with a .44 Special.