I think what we get sidetracked-by here is the distinction between "good" and "fine" guns (or even "best guns"). Mass-production of anything provides both benefits and detriments. In this "New World" as Ted has identified it (I.E., the United States, post 1850 & our Civil War or the... "War of Northern Aggression") was a period of rapid growth and industrial development in this country. For better or for worse, there was a huge need for tools and other implements (which included firearms) as the vast interior of these United States became more settled and domesticated. The mostly hand-made guns (that we so-dearly love here) were only being produced in very small numbers and for a very select audience, namely the wealthy and the then-growing middle-class of both Great Britain and the Continent. A natural outgrowth of both our Revolutionary and then Civil Wars here was a nascent firearms industry, which besides millitary weapons also began produced sporting and hunting arms for our rapidly expanding country (and our economy). A gun in those days was more "tool" than art and was arguably a critical necessity. Having the means for procuring such a "necessity" wasn't guaranteed in any way and many folks went without (unless you were part of our own growing middle-class, which by the 1880s-1890s was becoming something of a force here too). The Golden Age of American Double-guns (late 1880s to the 1930s?) was a natural outgrowth of American industrial might (& wealth) and the expansion of our own "middle class" to the point where we became consumers of better and more-refined hunting implements. Mass-production was arguably the only way that burgeoning demand could be met and boy...did we ever. Some of our "Golden Age" guns were pretty spectacular, as Dewey Vicknair points out in his discussion of the subject (referenced here earlier) but they never have (nor will) approach the level of design and build-quality of the guns of Great Britain in their great sporting "Epoch", which largely ended with the First World War (when so-many of their skilled working-class men, and of-course their customers, were killed or maimed). The forces that produced the Purdey sidelock are not the same as the ones that produced the LC Smith hammerless gun. Comparing them is arguably a fool's errand.

Edit to add that you can fully appreciate each of them for what they are (and are not) and... it's not a heretical act. Both examples are getting rather-old now and have become cherished artifacts from a rapidly-departing age. Both were clearly designed with a very-specific purpose in mind, and seemingly both gun-designs were very successful. And finally...there is still room in my gun cabinet (& life) for examples from both of these worlds and I remain immensely grateful for that fact. May it ever be so.