Jeff,
I should have also mentioned this.
The Williams FP and Firesight replaces a Lyman 66 that "disassembled" itself at the range. I just sent the Lyman back to Conneticut to be repaired.
When I switched from the buckhorn sights to the Lyman, my group size dropped from 3" to 1 1/2" @ 100 yds. Just for fun and to get rid of some Speer ammo I had loaded, I sent 100 rounds at the 100 yd gong at our local range. I hit it damn near every shot. I was sold on a peep sight for the gun, enough that I installed a Lyman 57 on a 50 cal GPR muzzleloader that I was building.
The Lyman 66 has a better sight picture than the Williams, but in terms of quality of manufacture, I don't know. As for Customer Service, well, we'll see what happens.
Matt