6 of one, half-dozen of the other. It's more of an aesthetics/style thing than a practical matter.
Personally, I'd rather not have a full lug, and I much prefer the 4" N-frames, but if you like full lugs, the 5" is quite nice.
With "mild" loads (lets say under 1,200 fps, under 300 gr.) you aren't going to need any help from extra heavy barrels or extra length up front.