Howdy Jake,
I have a pair of Old Model Vaquero's that I shoot. About 4 years ago, I installed the power custom half cock hammers and really like them. The two advantages on the OM is that when you 1/2 cock, and open the gate, the cylinders are indexed for unloading/loading. Something that Ruger fixed with the new model, but you know that. The other advantage is if you should accidently "slip hammer" a round, the hammer stops in the half cock and you can pull the hammer back to full cock and fire that round without having to "go around the horn" so to speak. I highly recommend them.
I had to send one of the hammers back (after 4 years and about 5,000 rds) as the hammer plunger somehow got bent and jamed. As a result, it wouldn't cock. Power custom sent me a replacement in nothing flat, no questions ask. Great service. Only thing was, they quit making the OM hammers and sent me a New Model hammer. It fits, the only issue I have, is the hammer thumb profile is slightly different then the the OM. I do like it better!. So I have an order for another hammer, to maintain some consistancy between my pair. More of a personal preference.