If OWB is the only carry method I would use, I'd pick a 4 inch barrel. If IWB or concealed carry were considerations, then the 3 inch barrel is the better option.
Open carry is pretty normal in the little town in Idaho where I live. I did own a Ruger SP101 with a 3” barrel but it only carried 5 rounds. That gun is now in my wife’s nightstand loaded with .38 specials. I did like it’s balance a lot and it was fun to shoot. However I want to load buffalo bores and have 7 chances to stop that PO’d grizzly which every year seem to get closer to our little ranch. I do have a 10mm pistol but it is darn heavy. I don’t really need 2 more pistols…guess I need to find a shooting range that has both and see which one feels better balanced.