"Best" covers a lot of territory. Best in accuracy? Best in reliability? Best artistry in the carving or engraving? Best grades of wood? Best for what purpose: hunting, reenacting, target shooting?
What style you looking for? A Lyman is a "pretty good" version of a Plains rifle and won't break the bank. You'd have to at least double the cost for a custom that would beat it in any category.
TVM makes a good product and is "somewhat" production, yet custom made cafateria style as you wish. The difference is that you get a good representation of what the original firelocks looked like (not the washed-out modern versions that have no distinct style).
The "Best" quality muzzleloaders are up in the 10's of thousands of dollars, but are no more reliable to shoot or necessarliy more accurate. You could buy a couple new Cadillacs for what the top end rifles sell at.
A truly authentically made, buy not necessarily "fancy", reproduction of a period rifle will set you back 10 or 12 grand, the forged iron barrel alone blowing your budget. :shocked2: But you could put your budget into a good barrel and lock and have a rifle that would shoot just as well and possibly better for under $1,000. Which would be "better?"