I have had experience with 1863 Remingtons from CVA (Manuf - ASM) and from Pietta of a much later vintage. The CVAs were good quality but fit and finish was not that of the Pietta.
I have two 1860 Colts from ASM (Brass Frame) and lock up and fit and finish is good. One of these revolvers started as a kit and was marked CVA. I restored the revolver, removing the CVA markings but leaving the ASM logos and now these two revolvers are essentially identical.
I have an ASP 1860 Colt steel frame (Nice looking unblued revolver) and it is a very good, tight, revolver. It had what I think is either a design or manufacturing flaw in that the barrel was made such that the roundball on the chamber would not pass the barrel to get into the ramming position. Smoothed the barrel where the arbor enters and that fixed the problem.
I have a couple Euroarms revolvers with the following thoughts.
1851 Navy is pretty good but also had a manufacturing flaw in the cylinder. I replaced it and the pistol works fine. Good consistent shooter.
Rogers and Spencer is very good. When I bought it, the previous owner had exchanged the toggle screw that retains the loading lever with one he had apparently made. I replaced it and one additional screw and now this revolvers looks and shoots like new. Very fun shooter. (Gotta watch the plunger screw because it likes to back out.)
I have an ASM Walker and Dragoon. I believe CVA imported Walkers and Dragoons manufactured by ASM. Mine have no CVA markings. The Walker is a very emotional revolver to shoot. I have not fired the Dragoon yet.
In some auctions ASMs and ASPs seem to comand a higher price than is reasonable. I don't have good familiarity with collector value of some of the ASMs and ASPs that might be very rare. But I think there is no reason to pay more than about 180.00 for a steel version of either an 1860, 1851, or 1858 assuming that it is in good condition. You can buy a new Pietta from Cabela's for 200.00 and I see no reason why a previously owned ASM or ASP would outperform a New Pietta.
I just bought a new 1863 and it is desirable over the ASMs
I also bought a very recent 1858 Remington with a six inch barrel and while operation of the revolver is no better than the two ASMs, the cylinder removal and reinstallation is the smoothest of any Remington I have ever fiddled with.
Some re-enactors like ASM because very few markings are visible unless you look at the underside of the barrel.
My reading of history convinces me that most bad government results from too much government. Thomas Jefferson