I shot the DPMS MK12, 18", 1:8 barrel in 3 gun for 4 years. It did not like wolf ammo. Otherwise, it was a very good barrel. DPMS are good barrels to start with. Mine shot .75-1.5 MOA with most ammo. Even after 4000+/- rounds it was a 1.25-1.5 MOA shooter.
I wanted to replace it with a 16" Wilson combat lightweight, 1:8, but they were never in stock. Wilsons makes very good barrels.
I ended up with the Rainier Arms medcon 16", 1:8, NATO. It is very light and much more accurate than the DPMS. The Rainier barrels have the 5r polygonal rifling. Easier to clean and you pick up a little velocity. My 16" Rainier shoots a little faster velocities than the 18" DPMS with 6 land and groove rifling.
There are a lot of very good barrel makers out. Set a budget range and get the best value within that budget of those manufacturers.