I have a 19-3 with a 4" bl and a 28-2 with a 6" bbl.
Got the 28 about 2 years ago for just under $500 OTD from my LGS. It is in nearly perfect condition and came with the original magna grips..no diamonds though as mine was circa 1978 IIRC.
My 19-3 I got about 5 years ago for the same price of just under $500 OTD from the same LGS. It has a little bit of honest wear in the finish at the muzzle and a couple of other places a holster would rub. This one shipped from Springfield in 1971.
Both enjoy advantages over the other that are very situational.
While the 19 seldom sees 38spls, I don't shoot it that often. It's one of my carry guns for going out in the woods. I don't find it punishing to shoot full house 140-158gr mags at all.. It is VERY accurate.
The 28 on the other hand doesn't carry quite as comfortably, but can be done with a descent holster and gun belt. Unless going shoulder rig, it's not very conducive to concealed carry, but again, when I go out in the woods where I carry open, I like the old Patrolman on my hip. This weapon is also deadly accurate, but is SOOO much smoother shooting mags. I often joke that I could fire mags out of the Patrolman with no grips on it at all. LOL!
As others have said, the Patrolman is going to handle a steady diet of full house mags better over the long run, and will be smoother shooting for the person pulling the trigger too.
I had a set of N-frame square butt target grips kicking around so I swapped them on to see how I liked it..they stayed..
Based on your criteria, I would say the Patrolman will suit your stated needs best. But seriously, don't deny yourself the pleasure of owning a m19 sometime in the future. There is a reason that the 4" K-frame Smiths are so incredibly popular.
Hey Sarge: Here is my Patrolman with target grips..