Thanks for the kind words, my friends. Getting ready for winter has kept me busy and away from the keyboard these past days.
The pinfire system was a very clever idea, which was not in any way lessened by the better and more successful centre-fire system which replaced it. The pinfire was in use for several decades in France before appearing on the British market in the late 1850s and early 1860s, where despite competing simultaneously with the early centre-fire, it reigned supreme for roughly a decade. Produced by the 'best' makers and unrecognized craftsmen in the back alleys of the Birmingham gun quarter, for the sportsman the gun of choice was the pinfire.
Until it wasn't.
For the most part the British sporting pinfire was a largely hand-made gun, with steam-powered machinery and machine-made damascus tubes only starting to appear in the waning years. One of the reasons the pinfire is not highly appreciated today is that it is easy to compare it with its descendants. Tall hammers and prominent levers can't compete with the sleek, balanced hammerless game gun - though many a graceful design feature of the perfected Edwardian double gun made its start in the pinfire, such as top- and side-levers.
I prefer to appreciate the quality of their construction, and their ingenuity. As the OP said, there are some gorgeous ones that appear on the market from time to time.
While I have gone the route of loading reusable brass cases in the past, it is a tricky business to get the pressures just right, and I was never completely satisfied. Even pinfires that have not been 'shot out' have likely seen more shells than I can realistically imagine, and 'obsolete' guns are never carefully looked after. 160 or more years of inattentive storage is not a good starting point for testing gun barrels, and I have chosen to retire all of my pinfires from active shooting. Should someone start manufacturing consistent-quality black-powder pinfire shells I might reconsider, but I'm not expecting that to happen anytime soon.
Are they worth the trouble? For shooting I would definitely look elsewhere, but for sheer enjoyment of the Victorian gunmaker's art, there is no finer gun to own.