I had a 4" S&W Model 29 Mag na Ported back in the 80's. It did nothing for muzzle rise, and just made for an impressive, fiery, "V" when fired in low light. Lots of fouling at the front sight too. I never noticed that it made things louder though.
A couple of years back, I picked up a 3" S&W 696 that was a Lou Horton gun, that came with factory Mag na Porting.
As far as the porting goes, nothing has changed in 30 years, and the fouling is even more annoying with the SS gun.
This is what things look like after 50 rounds of 44SPL LSWC's. In reality, its only about 10 rounds, as you have to keep wiping the sight off every other cylinder or so.
If you look close, theres an orange insert in that front blade. The powder fouling is bad enough, the lead is a ***** to get off, as it fuses to everything.
Now, if you use plated bullets, things are a lot better, at least as far as the lead fouling goes.
50 rounds of plated lead bullets looks like this....
Either way, it doenst take long to lose that front sight to the fouling, so if youre shooting a lot in practice, bring a rag, or lead wipe.