I am an old guy. I grew up with Smith and Wesson. I have had S&Ws for many years and they feel right to my hands.
I am also a gunsmith.
So with that said, and speaking form the standpoint of a gunsmith...........
Ruger GP100!
I don't own a GP100 because I feel better with my old S&W m-27s and M28s, but from the standpoint of design and reliability, you just can't beat a GP100
I just wish Ruger would make the 4" and 6" barrels in a light weight version. I hate all the extra unnecessary metal they leave on the barrels.