having bought new and used ready to fire offshore trad ml's from both italy and spain, as well as their "kit" guns, since the early 70's, they're all nowhere in the league of an onshore *USA* built gun, using top shelf quality components, built by a good and reputable gun maker. just NO comparison.
this is not to say they're all bad, it's just that they all have issues and most notably the flint versions, due specifically to the locks used. as mentioned within other posts of this thread, the lock geometry is passable at best, and due to poor (or nonexistent) quality control, some are just pure junk.
what this does to a newbie trad ml flinter pilgrim is leave the ml game entirely or pursue a cap lock. this is really too bad, since most of us know the problem isn't that it's a flintlock rifle, it's typically the lock itself, along with the flintlock learning curve, that stymies the newbies.
no wonder the NMLRA is thinking seriously about allowing zip gun inlines into the organization, in order to bolster their membership due to all the old timers dying off and the ever thinning ranks to replace them.
i have no allegiance to any of these import manufacturers, but based on personal experience with more than 2 dozen new and assembled of their rifles and pistols, investarms is still the better value, and is sold under brand names such as lyman, cabela's, diixie gun works, and others. quality control is still spotty and ALL require tweaking and fondling ... but if done right, and with a little luck, they can make decent guns for those wishing to get into this game and/or infrequently shoot. but they're all stepping stones at best, imho. once hooked on a flinter, acquisition of far better gun will be imminent. typically sooner than later. which is always a good thing. ymmv.