I don't have a .22 six shooter, but I do have a Ruger New Vaquero (45 Colt). I compared it heavily with the Uberti (which was much less expensive). The craftsmanship of the Ruger was so superior, I just couldn't go with the Uberti. This is in no way meant to impugn Uberti--I know nothing about the company, but I was told they were high quality for the price.
I have a Ruger single six and Blackhawk 357. I also have an Uberti SAA clone in 45 Colt. the uberti is a nice gun but it is no Ruger. Having both I would recommend the Ruger over the two mentioned.
I collect and shoot both Ruger and Uberti single actions. Nothing wrong with Uberti guns they make some nice ones. For a .22 Caliber however I would go with the Ruger. Unless you just have to have a new gun, lot's of nice used Single six's and even convertables with the 22 Mag Cyl. in the $275-$350.00 range out there. Just make sure if you buy one with the 22 Mag Cylinder, it matches the gun. The last three digits of the gun will be electro scribed on the face of the cylinder meaning it was factory fit to the frame. Another tidbit of info is get the Single Six with adjustable rear sight.
I'd have to go with Ruger. The craftsmanship is awesome. It's a smooth single six that just feels right. Very accurate too! Fun too shoot but heck any gun is fun to shoot, at least once!
I think the Ruger for a number of reasons. One of the questions that occurred to me when I was considering your post is do both pistols allow you to safely carry a round under the hammer? I know the modern Rugers do, but does the Uberti?