I have two Old Vaqueros and a New Vaquero with the Birdshead grip and 3.75" barrel. The two old guns are .45 Colt and the Birdshead is 45 ACP. I think realistically, the New Vaqueros will handle any .45 Colt load I would want to use, meaning a max 10 grain Unique/250 grain swc. I have actually backed that load down to 9 grains of Unique now, and the smaller New Vaqs should handle that easily. My new Vaquero, of course, exists on a diet of 230 grain hardball. I have only owned one Uberti, and it left a very sour taste. I understand their QC is a little better now, but I ain't taking no chances.
The Rugers, of course, aren't perfect. I don't know about the other calibers, but if you get a .45 Colt, go ahead and order an increased strength base pin latch spring. I don't know why Ruger doesn't address this problem, because it has been around since they started making big-bore revolvers. The cylinder base pin will jump the notch on the latch under recoil and back out, causing all sorts of (potential) problems. Also, cylinder throats on some guns have been notoriously tight, especially on the .45s. I have never encountered that particular problem until recently. The (Old) 3.75" Sheriff's Model I bought a couple of years ago will not print a decent group at 15 yards. It is all over the paper. The trigger pull is atrocious, but I don't think that is all the problem. I am going to see if I can mike the chambers. They should be .4525 I am told, but it isn't unusual to see them as small as .449 or even smaller. This wreaks havoc with accuracy, and can increase pressure. The triggers, by the way, tend to smooth out after a few thousand rounds/dry fires. Also, a "poor boy's trigger job" helps. Go to the Gunblast site and look that one up.
Here are two of my Vaqueros, an (Old) Vaquero, and the BH grip New Vaquero. I have been shooting that ss Birdshead gun a whole lot lately, and it is just a hoot. I have been practicing some hip-shooting at 7 yards, and am getting good at it.

I love the looks and feel of the large frame gun, but I am going to have to do something about the accuracy. I had to file the sights on the Birdshead gun to get it to shoot to point of aim. I am toying with the idea of having the old gun cut back to 2.5 inches and the sight re-soldered, having the ejector rod and housing removed, and making a true Sheriff's Model of it. I think the original Colt Sheriff's Models were three inches, but the 2.5 inch S&W 19 is so cool I'd like to try it on a Ruger. Hey, it's only money!