I know from the two Colt replicas that I had, the Ubertis are better, stronger steel, fit and finish are superior. The Pietta Remington is tempting, cheaper too. But, I just sold off my Pietta 1860 Colt at a local gunshow yesterday and only got half of what I paid for it after only having it a year. The gun shot really well, but the mechanics were lousy.
At this point I would prefer an Uberti 1858 Rem. and another 1860 Colt, but Uberti. My Uberti 1851 Colt had problems though, loose loader rod holder on the barrel, good glue fixed that. And the tolerances of the wedge-to-cylinder rod are tight, takes a technicque to put the gun back together. Otherwise the 1851 is a keeper.