There's no question, unless you want to drop huge money on a Freedom Arms custom SA, Ruger is the best hands down. No reason to buy an Italian copy when you can buy a true American single action from Ruger. Italy makes some very good replicas and some very bad replicas but Ruger makes even better guns all day, everyday. Colt also makes a fantastic SA that has a long historical timeline and is an excellent choice if you don't plan to ever shoot anything but the lower power "cowboy" ammo.
I've got a large frame Vaquero, two New Vaquero Bisley's, a Blackhawk Convertible all in .45Colt plus a Single Six Convertible .22LR/.22WMR. You just can't buy a better single action without moving up to the Freedom Arms. I say buy American and support American gun manufacturers, especially in this time where our second amendment has been constantly under attack.