I've got an unmatched pair of full-size Beretta PX4s - an F version that I bought new, and a D version that I bought used. The slides for both were sent to Langdon Tactical for identical Ameriglo sights, plus the F was converted to decock-only. I've installed a 12-lb. hammer spring in each and the DA pulls feel identical though I haven't measured them. I can't distinguish an accuracy difference between them; bullet holes appear right on top of the front sight with either. I've got about 4k rounds total through both guns, mostly my hardball reloads with some factory hardball and a few hundred 124-grain +P HSTs and I'm still waiting for the first bobble from either.
I'm trying to figure out which I shoot better so I can concentrate on that one and also buy a backup/training copy. I'm comfortable with DAO since I shot an S&W K frame in IDPA for several years and I'm also comfortable with the DA/SA transition from my previous CZ-75B carry guns.
Today was my first try. I was a bit hurried so I used the 5 Yard Round Up, running it twice with each gun. Results were inconclusive. Scores and splits were close, with a slight advantage to the D version in the support-hand-only strings. Not enough data yet.
I'm going to try again using the Hackathorn test, and maybe the Super Test if time allows. Recommendations for other methods will be gratefully accepted.