I have four, a sidelock Damascus barreled 12 gauge from about 1886, and three box locks of varying grades post 1905. I would agree Pieper most probably never made a "best" gun, but they made some nice ones. I'll post a couple pics when I get home tonight.
My three fluid steel barreled guns are all chopper lump and vary between a field grade and 100% coverage engraving.
Echoing Mike I would advise "buy the gun, not the maker". Pieper will never command much for brand value but I think I got some pretty nice guns for not very much money.
Pieper was an early pioneer of relative large scale and vertically integrated manufacturing as well as having a number of patents to his name, most importantly his system of joining the barrels, a system used to this day most notably by Beretta. He was also a founding partner of FN.