There are several (maybe 12 to 18) top notch makers of muzzleloader barrels. Who is the positively best depends on the purpose and use of the barrel. The twist, shape of the rifling, width of the lands/grooves and depth of the grooves is what matters. Some are more for one type of shooting than another. Bench rest barrelss are then again something else all together. The makers mentioned above are all among the best. There are a few lesser known barrel makers who will custom design and cut a barrel for the customer. I understand Bobby Hoyt in Fairfield PA is one of these. Years ago I went to a guy called Hoppy, of H&H barrel works (Now defunct I hear) Hoppy and I actually did some target shooting together in his shop while we discussed what I wanted in a barrel and he came up with a slight variation on the design he was already making and cut the barrel special for me. (the rifling was similar to Pope rifling but adapted some for a muzzleloader, even has a slight choke bore at the muzzle) That was in 1978 and it is still the most accurate barrel I own.
Over the years I have swapped for other barrels and guns with all kinds of rifling. Square bottom narrow grooves, wide bottom grooves, shallow grooves, deep grooves, gain twist, even a gun that had rifling that was deeper at the breech than at the muzzle. Choke bores, etc.
Some barrel makers will tell you that this is what you need. Sometimes it isn't the optimum choice. If you want a classic heirloom grade hunting gun, most of these are good. If you want a specialty muzzleloader barrel for 25 and 50 yard offhand round ball competition, you need something else. And some of those guys don't even have the tooling to make the special barrel.
Offhand competitors want a fast twist, round ball rifling depth, light weight barrel, that they can shoot with 20 or 30 grain charges. These pea shooters can be made with thinner barrel walls due to the minor powder charges. Therefore they are lighter and it isn't as fatigueing to raise and aim the rifle 100 times in an afternoon.
For most folks, a Getz, Rayl, Long Hammock, Colerain are all equal high quality. Unless you are getting into specialty competition shooting like International Muzzleoader competition, they will do just fine for you.
A lousy shooter is still a lousy shooter even with the best equipment. Andd a truely good shooter can still shoot well even if handicapped with lousy equipment.
One of the disadvantages of having the best equipment is that all flyers and lousy shots can only be blamed on the shooter.
If you are thinking of building a gun, or having one made, don't skimp on the lock either, get the best you can afford. In fact, get the best and then have it polished and fine tuned by someone like Brad Emig in Hellam Pa. I have an older Curley North Star smoothbore. Not sure what lock Curley used, but the inside was polished like a mirror. That gun goes off so incredibly fast that you don't even hear the Flint hit the frizzen separate from the gun going off.