I like the clean lines and durability of a fixed sight SA. But they are NOT my first choice for a woods / hunting revolver.
Your odds of finding a SA with fixed sights that shoots exactly to point of aim with your favorite load is small. And POA grouping is important in a field gun.
Unlike a paper target at the range, where multiple shots are being fired, and bullet impact can be judged on paper, then compinsated for via Kentucky Windage, grip adjustment, etc., its different in the woods. At least when shooting at game, your first shot is usually going to be your only, and best shot. You don't need to be trying to figure 4 inches to the left and 2 inches low, at 45 yards, while trying to nail a nervous cottontail. And I for one appreciate being to use different loads depending on the purpose. Seldom will they all shoot to the same point of aim.
Actually, probably, most shooters would be well served with a fixed sight SA that was reasonably close to POA. General plinking, rolling a few tin cans, or an unlucky squirrel. But when you say field gun, I think hunting as well. A serious guy who hunts and wants to be able to hit at a variety of ranges will apricate not having to apply Kentucky Windage on an already difficult shot at a potentially small kill zone.
For what its worth, I have been a pretty serious handgun hunter for almost 50 years, and all my Ruger SA's I hunt with are adj. sights. The one exception is a fixed sight Bearcat that shoots exactly to the sights at 25 yards with CCI HV HP's. Just my view, anyway.
Larry