I am finding a brass framed Remington style pistol with a 12 inch long barrel which is called a 1858 Buffalo Brass Frame Revolver .44 caliber in the 2005 Cabela's catalog for about $160.
In the same catalog I see a 1858 New Army .44 Caliber offered for about $160. This is a steel frame gun with a 7 7/8 inch barrel.
Which is best for you? IMO, that depends on what you want to do with it.
If you want to shoot it with light loads and you like the super long barrel and it's good looks go with the brass framed gun.
A lot of people don't care but I will mention that such a gun was never offered during the Civil War because there were no brass framed Remingtons made, and there were none with a 12 inch barrel but that is only important if you want a gun which was like the originals.
The reason I say "light loads" is because brass is weaker than steel and some people have damaged their brass framed guns by shooting full power loads in them.
Using light loads, these guns will shoot for a long time.
If you want a Remington that can shoot full power loads all day withuot overstressing the frame and is a fairly close recreation of the original gun, I would favor the steel framed Remington if it's still available. Especially if the price is the same.
I can't speak to the accuracy of the Buffalo pistol but the accuracy of most of the reproduction guns seems to be a matter of luck.
The closed frame Remington design is usually a bit more accurate than the open top Colt design.
That said, remember, both the Colt and the Remington pistols were made as military weapons. They were not target guns and in this, the reproductions seem to be a fairly good copy.