As a general rule of thumb, any Mauser built during peacetime was top quality.
Rifles built under contract by DWM, FN, and Steyr for other countries are always good quality.
The bottom of the barrel are the absolute "last ditch" German and Czech Mauser's made in the last days of the war.
Quality of both steel and manufacture suffered, but the quality actually stayed up there until almost the last minute.
As far as pure quality of workmanship, the tops are the 1909 Argentine and the 1908 Brazilian model 98's made under contract by DWM.
The 1909 Argentine is the finest quality Mauser military rifle ever built, and these were as well finished inside as most modern guns are outside.
Back in the 80's I read an article in a Guns & Ammo Annual about why custom gunsmiths prefer the 98 Mauser.
The author said that to manufacture a 1909 Argentine to the same quality of workmanship, the rifle would cost about $3000.
The Price would probably be double today.
The 1909 was the only military Mauser made with commercial features like the hinged floor plate with trigger guard release, and the pear-shaped bolt knob.
The 1908 Brazilian is not far behind.
For a good rifle, most any of the FN Mauser rifles made in the 1920's and 30's by FN for South American countries will be excellent.
If you can find one, the rare FN Model 1950 in original 30-06 made for Belgium and Belgian's Congo colony are some of the best ever made.