Quoted:
Chrome lined barels will easily outlast stainless. Nitride IMO, is the best option at the moment.
+1
Given the option of chrome lined vs. chrome moly.
Chrome lined barrels will be easier to clean, less susceptible to corrosive ammo (rust/pitting/etc), and can last several thousand rounds longer than a basic chrome moly barrel before accuracy completely falls off.
When talking QUALITY barrels, most shooters (especially in ~16" AR platforms) will not be able to tell the accuracy difference between chrome lined or not.
Some people talk like chrome lining will bring you from .5moa to 3moa. Not true, the difference is fractions of MOA in most situations.
Chrome lining really shines if you're going to get your rifle HOT and keep running it...or mistreat it and clean it infrequently...or if you live in a jungle!