Until I started surfing websites looking for a spare barrel, I had never encountered 41V50.  Better than 4150?  4140?  With nitride what does that do to the barrel life?

https://www.ar15.com/forums/ar-15/4150_vs_41V45___Whatandapos_s_the_superior_barrell_/118-590878/

Nitriding will only increase the surface hardness of either.

Depends on the manufacturer. 4150, CMV, they’ll get the job done if made right. Nitride is good to go but I’d always advise some skepticism with it. Cheap barrel makers use it because it’s cheap, and the benefit of nitride is lost on a barrel that was shit to begin with.

If you want a good cheap barrel with a good track record I’d go with Green Mountain, Expo Arns, or DSA chrome lined. Not because of the chrome lining specifically, but because high quality nitride barrels are limited to just a couple manufacturers. Those guys are typically reputable sources of sub $200 barrels.

The quality of a barrel is not determined by the finish or the base material (unless it's a grossly substandard material selection).

41V50 is the same as 4150, except a bit of vanadium is added to make it a tad harder.  41V50 is also known as CMV, or Chromium-Molydbeum-Vanadium, the three major alloying elements.

4140 has the same alloying elements as 4150 but one point less carbon, so a tad softer.

Best to good:

CMV w/ chromium plating
4150 w/ chromium plating
4140 w/ chromium plating
CMV nitride
4150 nitride
4140 nitride
CMV bare
4150 bare
4140 bare

But, as stated above, quality in manufacture trumps material.

A bigger variable is Cold Hammer Forged vs Button Rifled, which seems to ~2-3x barrel life vs button rifled.