I think the MOA is a more contemporary American trigger in that it matches the dominant shooting application. Most people are concerned with bench accuracy and a light, adjustable trigger is conducive to that. A few old curmudgeons (myself among them) put equal or more weight on field durabilty and like the simplicity of the old exposed trigger. I refer to it as an American trigger because in other places they do not prioritize accuracy so highly. My limited experience in Africa is that they put a lot more emphasis on 100-150 yard quick accuracy and second shots (as opposed to hitting a 400 yard clay pigeon) than we do.
If you have ever had an enclosed trigger go wonky in below zero temps, you appreciate the old design, even if it can never be tuned to varmint rifle levels.
This.
Out of 5 MOA's none needed adjustment for me. Can't speak to durability because I have not used them for 30-40 years.
While on the subject,and along the lines of what Utah said above, I got an earful from an old pal last week up in Maine about enclosed triggers. He is an experienced competitor and hunter so we have that out of the way.
He had canoed back into the Allagash during deer season,living outdoors for a couple of weeks. Into the hunt he hit a couple days of drizzling rain,followed by snow and temps in the teens.
His enclosed trigger froze solid and the rifle would not function.I won't mention the rifle make, only that he is lefty....He pulled the rifle apart and somehow got the trigger thawed with hot water and dried enough.That far back in, he was out of commission and could not hunt until he fixed it.
I was not surprised as I have seen the same thing.
As a competitive shooter and active hunter, his view is that enclosed triggers are fine on target/varmint rifles but not the trick for a wilderness rifle or one used under adverse conditions. He said that we get too carried away in the quest for accuracy and sometimes leave dependability and ruggedness on the table.
He asked me to find him a left hand M70 Classic in 270....said he'd rather carry a heavy rifle that works than a light one he couldn't depend on.
