IMHO, the large frame guns are way too much beef for the .357 cartridge. The guns are too heavy and too imbalanced. The mid-frame guns are much better suited and do not lack for strength in this chambering. That leaves us with the New Vaquero, 50th anniversary Blackhawk and the Old Model Blackhawk. The OMBH will be the lightest as it will have an aluminum grip frame and post 1962 models have an aluminum ejector housing. My little 4⅝" flat-top .357 (1958) weighs in at 38oz and that is a good place to be. The same gun in a 50th anniversary model will come in at 44oz, which is a substantial difference. The New Vaquero will be slightly lighter. Even so, these guns handle much better than their large frame brethren. Like a Colt SAA and no single action handles better than that!
While I have several sixguns with fixed sights, adjustable sights are imminently more usable. Not just for their adjustability but for their superior sight picture.
All that said, in my opinion, a good Old Model is one of the best .357 ever produced. The "eared" models like this can be found at reasonable prices.
While the flat-tops (1955-1962) are more desirable, both to shooters and collectors. Which is why they cost more. This one cost 2½ times what the eared model above did. For me, it is well worth the premium as I greatly prefer the XR3 grip frame (dead ringer for the Colt SAA/Navy) over the later XR3-RED. Which has too much room behind the triggerguard. The flat-tops also tend to be finished a little nicer and had steel ejector housings. For me, this is the perfect .357Mag.
Your best bet may be the 50th anniversary model of 2005. This was the first of the New Model flat-tops and they are very, very well made sixguns. They can still be had for reasonable prices and unlike the Old Models, they are all steel. Here's a shot of mine, which has since been traded away. Giving in to my affinity for Old Models.