Dang!!!
I like them both but in the end, my personal revolvers are Uberti's. The finish is usually superior, the parts are the best parts ever in a cap gun ( that's where the price difference is). The short arbor is the obvious negative but is easy enough to fix. Also, Uberti barrels have fast twist rifling making conversions (45C) much more compatible. Not to mention, I'm a Dragoon fan so Uberti is the only game.
On the other hand, Pietta's are less expensive and Don't have the short arbor . . . 2 big pluses for the average shooter! They and Uberti's can be made into the same "tough as Ruger" , fast and reliable revolvers. So in the end, they are the same animal in that respect. The parts in the Pietta are modern production (injection) close copies of 70's type parts which means they take more work to get to spec. or for the out of box user, a heavier main spring is needed because of the parts mentioned. Uberti's mains are lighter because of the higher grade parts.
This goes across the Remington models as well but again, either can be made into the 19th century Ruger equivalent!!
So, whichever you prefer, it's all good and definitely can be made better!!
Mike