I have most of the "N" frame S&W revolvers. I find the double underlugged barrels to hold much closer on target. However, I prefer to pack the slim barrels (as in my 624).

I have two 625's - one is a 4" JM Special (625-8) and the other is a 625-6 Model of 1989. I find my self shooting the 5" more as it seems to hold just a touch better. The difference is not great but it IS there. It did take me a while to enjoy the extra weight of the double underlugged barrel (maybe it's kind of like lifting weights at the gym - a bit of regular "doing" will allow you to reach a higher level of proficiency)?

At any rate, it is simply a matter of what YOU prefer. We are not all alike (thank the Good Lord for that!). I am a "Certified Old Fart" but am NOT a wimp (if that makes any difference). I have decent upper body strength for my age and as far as shooting is concerned, I prefer "weight forward" revolvers, for steady holding.

One more thing - recoil recovery is faster with a heavy underlugged barrel, if that is important to you.

FWIW
Dale53