Uberti is considered better. Pietta has made major improvements and reportedly, have greatly reduced the lemon rate. Mine is a 2010 dated one and in my opinion, the quality is good enough. I actually was talking to the American Rifleman editor in chief about this. He still believes that Uberti's are superior, and he's probably right. However, that that is not to say that you will not be satisfied with a Pietta. They are an amazing price and you will definitely get a shootable product. If you get it from Cabelas (the best price I can find), you get their warranty and if you get a lemon, they will make it right.
My 2010 Pietta Colt Navy only has one problem. The bolt is a little thin so there is some lateral wobble as it sits in its place. The exposed part of the bolt is actually a bit undersized to the cylinder notches. The result is that the cylinder wobbles just a little bit and it can fire not perfectly aligned with the barrel. It does not affect accuracy however. The ironic thing is that prior to 2010, one of the common complaints about Pietta's is that the bolt was too wide. Pietta does get other things right, such as the arbor length being as perfect as I can tell. The barrel also perfectly squares up to the cylinder face as a result. My wedge was nor forced in too tight like commonly complained about, but I did have to tap it out at first with a piece of aluminum. I did fit the wedge so I can use it without tools.