If you are interested in 357, I feel the Ruger New Vaquero is about the best single action 357 Magnum revolver I have seen. I like it better than the old Vaquero in 357 Magnum for a couple of reasons. The smaller size just feels better in my hands, and the cylinder indexes properly on the ejection port so you can load and unload more quickly. Like the old Vaquero, it has a transfer bar so you can carry it with six rounds in the cylinder. Like the old Vaquero, the strength of the revolver is more than adequate for any commercial load.
If you are interested in 45 Colt, the only difference may be in the strength of the action when compared to the old Vaquero. I would shoot any round through my 45 Colt New Vaqueros that I would shoot through my Colt SSA revolvers and USFA revolvers but would probably not shoot some of the heavy loads I sometimes shoot out of my old Vaqueros. I may be being too cautious for no legitimate reason, but I have old Vaqueros and Blackhawks for the heavy loads.
I really like my Colts and USFA revolvers but generally shoot Ruger New Vaqueros during matches and when in the woods.