As far as handling goes... unfortunately different people have different ideas - most experts seem to think a 5" barrel offers ideal balance (I agree), but I've heard many people say they like a 2" or 3" barrel best - personal taste figures in for sure.
As to my druthers, I have shot a a few 6" full lug revolvers, and thought them only a tad muzzle heavy - not problematic in that regard. Since the model 14 has no underlug, I don't think it'll be be bad either, even at 8&3/8". I do think you'll get some extra accuracy out of that sight radius - long barrels are illegal in Olympic bullseye shooting - for a reason of course.
Since some of this is just personal preference, guess best way would be for you to handle something similar - only you know if you'll like how it feels. Even though it seems very long today, this length was fairly common a few decades ago.