Would also depend on what you want out of your gun. When you say "Buffalo Gun" I take that in the historical sense. The 1885 Winchester is one of the best rifles ever made, but it ain't really a Buffalo Gun. The last profitable hide hunting was in the spring of 1883, they was not enough left in the fall to make a profit. NCOWS does not allow it for their buffalo shoots for that reason.
The Low-Wall was just a smaller action for smaller calibers, I have one that wasre-barreled to 22 Hornet in the 1940's.
The Trapdoor was a military design and it feels kind of like a club because that was it's secondary duty. Plenty of hide hunters started out with one in the early 1870's, Cody was a meat hunter, but that is what he used.
The Sharps is the famous one, it has it's good points and some bad such a a fairly slow lock time, heavy hammer and mainspring, plus a firing pin that has to go around the corner.
The Roller has a lot going for it, but most don't have a really good trigger pull and set triggers are scarce.
There were at least a few Ballards used on the hide hunts, they have a fast lock time and perhaps the best trigger of the lot, down side, they are expensive either repro or original.
Myself I shoot a Pedersoli Sharps I bought in 1994, to me Sharps just says Buffalo Gun. Probally not a really good answer, but an honest one.