4"
I carried a 4" N and K for years. I have a couple nice 6" but trying to carry them was a problem. If I carried with a lower riding "Border Patrol" holster, it was constantly in the way when sitting, getting into chairs with arm rests etc. If I carried the 6" in a high rise holster, it was under my armpit by the time the muzzle cleared leather. The cars we drive are getting smaller with more and more crap in them...MDT's, Laptops, Radios, light and siren box, AR-15 rack, Mobile camera etc..I think now, more than ever, the 6" would be an even bigger problem. If you just plan on wandering around the woods etc. I could make an argument for the longer barrel, longer sight radius, better velocity...
Moot point for me know. I have to carry the issue Glock 35. Still gets caught up in chairs. I'm 6 ft, 175. But, a 34 inseam, so, all my hieght is in my legs. MY torso is too short for the 6". Everybody is different though...
Another point, the lower riding holster that allows you better access to the gun is also harder to protect if you get into a fight or in a crowd. High ride holster, you can just clamp your elbow in while you deal with the problem