I have a Traditions William Parker .50 that I paid $370 for from Kittery Trading Post. It shoots just as accurately as my Pedersoli Le Page .44 that I paid more than 2x the money for. It is also, in my opinion an extremely good looking pistol. I have 7 BP pistols/revolvers, most costing more than the William Parker, but the Parker in one of my favorites to shoot. It does not have an adjustable sight, but is a perfect 6 o'clock hold on a B-8 target at 15 yards. Has a very good double set trigger too.
Love that gun, I would highly recommend it.
I would stay away from the less expensive Pedersoli's. I have never shot one, but from what I've heard the triggers leave a lot to be desired.