Hi...sorry to take so long in getting back to you; I was helping my kid move in downstairs plus a number of other things.
First, we have to be sure we're talking about the same guns...the Blackhawk and Super Blackhawk are available as Bisleys or (for lack of a better term) non-Bisleys. The Blackhawk and Super Blackhawk have adjustable sights. The Vaqueros (all of them) have fixed sights (blade front, grooved topstrap rear). They are also available as Bisleys or non-Bisleys.
The hammer on the Bisley guns is considerably easier to reach (not the 'stryne-ism!) than the non-Bisley. Many shooters don't have to shift their grip at all during cocking. The Bisley trigger is wider and gives better control for most shooters. The grip shape on the Bisleys is designed to put the barrel-line lower in the hand than the conventional "hawg-leg", giving better recoil control and consistency from shot-to-shot for the average shooter.
I wound up with a Vaquero Bisley (they practically gave it to me) and found that the grip shape didn't do much for me, as I have smallish hands. Add to this that Bill Ruger, president of the firm, had hands like catcher's mitts, and the grip was just too big for me. I replaced it with a birdshead grip frame from Brownell's (check them out:
http://www.brownells.com, I think they can ship to Australia). This grip frame is designed for the Blackhawk series, so I had a bit of metalwork to do...not hard, just fiddly. The result is a somewhat strange-looking revolver that shoots
very well...for me. I'll send you a pic via email, my email software knows how to squish these pics down to manageable size, but I don't, so I can't post them. Yet. In any case, I believe that Ruger is coming out with factory-fitted birdshead grips, although I have yet to see one.
The big point is, you can get the Bisley conformation in either revolver, so it's not a point to worry about. BUT...if you're talking about shoulder-to-shoulder bullseye matches, the adjustable sights certainly are a consideration. Get the Blackhawk.