When Colt 'reissued' some of their percussion revolvers, back in the '70s & '80s, Colt didn't actually manufacture the weapons. They bought parts 'in the white'--unfinished--from the Aldo Uberti firm in Val Trompia in Italy, brought them to the US, & finished & assembled them over here. I'd guess you'd have to say, considering Colt sold those guns under the Colt trademark & was very quiet for a long time about where they were actually manufactured, that Uberti makes the best replicas.
Ruger did not make 'replicas' of the Colt SAA. It made 'look-alikes.' A Ruger is entirely different from a Colt inside the grips. Colt used--& uses--flat springs. Ruger uses coil springs. The late Bob Bowman, who was probably the best of the 'fast-draw' showmen of the 1950s & '60s, used Rugers. He was also a custom gunsmith. He altered his Rugers to look exactly like Colt SAAs. When he told Bill Ruger he was using one of his products, Ruger didn't believe it. Bob had to take the grips off one of his sixshooters & show Ruger the coil spring driving the hammer before he'd believe they came from his factory.
Mine was made in 1906. Some idiot had it converted to .357 by Christy sometime in the '50s, so I had to re-convert it. It's now a 7½" .45 Colt with original gutta-percha grips. Bought it for $75 in '71.
Missed a jewel much earlier & have been kicking myself for it ever since. When I was in the army I was stationed at FT Knox. In a pawnshop in Lexington, KY, I spotted a factory-nickel 5½" New Service with RCMP engraved on the backstrap. It was .455 Eley. The price was $65. It would bring a small fortune from a collector these days.