My Buck Mark UDX outshoots my old Ruger Standard model, which outshoots the Mark IV Target, which outshoots the Mark II 50th Anniversary model. So to me, the Buck Mark is more accurate. Since Huntsman22 monkey-wrenched the S&W Victory into the mix (nice gun by the way), I also have one of those but haven't shot it enough to definitively determine where it falls into the accuracy list while in my hands. Preliminary results put it about equal to the old Ruger Standard model.
I encountered a few ammo-related problems however. Norma Tac 22 fired cases jammed and Federal AutoMatch sometimes failed to feed in the Buck Mark. Aguila SV produced several fail to feed problems (3 of 20) in the Ruger Standard, and fail to fire problems (5 of 20!) in the Ruger Mark IV Target before I quit shooting it in the Rugers. The only non-ammo reliability problem I had was a minor one with the S&W Victory, which was easily resolved by tweaking the ejector tab using the advice found on this website. No problems with it since.