But there is a compromise in handling qualities, especially with single action revolvers like the Colt SAA or Vaquero.
Yes, if you're practicing the Road Agent Spin or other fancy showoff techniques adjustable sights can cut you painfully...but if you aren't I don't see any penalty to adjustable sights, just the obvious advantage.
I traded off my Ruger Vaquero .44 Mag to get a Super Blackhawk
because it had adjustable sights.
Fixed sights are difficult, but not impossible, to adjust. Once....
I agree, ONCE. After that they're even more difficult if you need to adjust them ever again.
There are different schools of thought, neither is wrong, just not for everyone. I don't want to have to restrict my pistols to a certain load. I want them to have the ability to be easily adjusted for different loads and then adjusted BACK if/when desired.
I'll be honest, I rarely adjust my adjustable sights. If I'm only shooting a small quantity of something that doesn't hit point of aim, I'll usually just "hold off" but if I'm going to shoot more than just a few, then I want the ability to change, and then change back with a screwdriver.
Duty class/service class gun, usually do fine with fixed sights. Minute of man at combat ranges (or hopefully better) and always shooting the same (issued) ammo. Some of my guns are like that, and I'm not changing them.
Others are guns from which I want pinpoint accuracy, and the ability to do that with a variety of ammo. I won't deliberately buy a fixed sight .22. (specific models for collecting, aside) for general sporting use. There is no "adjusting the load" with .22 RF, other than buying a different brand of ammo. What happens if you can't get that exact ammo that shoots to point of aim? get out the files if its fixed sight, with adjustable sights, just the screwdriver.
Are adjustable sights more fragile? Yes. On the other hand, that's never been an issue for me, as I don't beat on things with my pistols, and in well over half a century the number of times I've dropped a gun can be counted on part of one hand. But, that's just me, and I know some people's pistol live a much rougher life than mine do.
If you're going to war and need a combat gun, fixed sights are probably the best (and do note that they don't put fixed sights on RIFLES) but for sporting use, I think adjustable sights are the best way to go.