Some outdated and frankly wrong info here.
1. Pietta and Uberti are not the same company, are not owned by the same company, and have no direct affiliation with each other. Pietta is not owned by the Beretta group.
2. The piettas of 20-30 years ago are not representative of what Pietta is manufacturing today. Pietta has considerably improved their quality and is now considered the best of the Italian repros almost universally among the SA crowd. The GW2 is highly regarded as the best Italian clone being made.
Uberti and pietta differ considerably not just in their firing pins and operating mechanism, they are also dimensionally different. The Uberti pattern is larger in several dimensions than a genuine Colt SAA and many parts are not interchangeable. USFA and Standard Mfg. both use the Uberti pattern, and many of their parts are also not interchangeable with genuine Colt parts.
Pietta stayed true to the Colt dimensions and some parts are interchangeable with a Colt SAA.
3. Uberti cheapened the Colt design in a few ways, one of which is the replacement of the staked boss that the Colt uses to retain the ejector housing to the barrel with a drilled and tapped hole into the barrel. Pietta is the only repro I'm aware of that, like Colt, uses a boss to afix their ejector housing to the barrel.
Literally the only reason I'd buy an Uberti over a Pietta is the calibers offered. Pietta doesn't have a .44 special SA that I'm aware of, while the Uberti model P is available in .44 special.
I bypassed all the Italian qc concerns by sticking with US manufacturers. I have a Colt, a USFA, and now a Standard Mfg on its way.
I'm not saying they don't each have their issues, but a broken hand spring on the SM or the rough internal finish on the Colt is easier to deal with than a soft steel frame.
The USFA is flawless of course. Find one of those if you can find one for a decent price.