Just got my 51 navy ubertia a few days ago and have put a couple hundred rounds through it.
In comparison to my pieta 51 they are very close in fit and finish, but the ubertia has a lot better action, no trigger creep and about a 3 lb. pull, and timing is near perfect. The pieta I had to put a new hand and spring and file it to get timing right, and had to stone the hammer sear to get rid of most of the trigger creep. The ubertia shoots a lot closer to point of aim than the pieta, and is shoots slightly tighter groups, posibly due to the better/cleaner action. The ubertia also has manufacturer info under the loading lever and out of sight where the pieta has it on the sides of the barrel. The color case was also better on the Ubertia, and the blue and metal finish were a little better. The Ubertia also has hammer safty pins on back of the cyliner to let you load all six chambers and keep the hammer off a loaded chamber where I had to put one on the pieta.
Only thing is the Ubertia requires 380 round balls as the next size down I can thumb press into the cylinder. It would probably do better with a 385 ball, but it's still very acurate.
Also the rifling on the ubertia is about half again as deep as the peita and very well honed. That may count for the increased acuracy over the peita.
I will definatly be buying Uberia's from now own, there not that much higher priced and for the money I'd rather not have to go through a gun to fix what they should have got right at the factory. Granted it wasn't hard but I've had to do no work the Ubertia where I've spent several hours on the pieta.