I almost started the same Thread last night , but with .357 included .
The .38 weighs 13.5 oz. & has a polymer frame . While the .357 & 9mm weigh 17.1 & have steel frames .
Out of that short barrel the 9mm will probably be faster than the .357 using the same ammo , but you could use heavier grain ammo in the .357 & shoot 38's .
Recoil could be a problem with the 9mm , it was in my 13.8 oz. M&P .357 , but that extra 4 oz. might help . I don't know if it would have the same felt recoil as the .357 , but seems like it would since the muzzle velocity is about the same or faster in the 9mm .
I don't know if I would like carrying extra moon clips . I like the speed strips , because I can put them in my front pants pocket , but you could load faster with the moon clips .
With the .38 being lighter , it would be more comfortable to pocket carry .
I think that if I were going to pick the 9mm or .357 , it would be a 3" model & not pocket carry .
Those are some of the things that I have been weighing .