I have a Olympic Arms AR (considered buy some as a lower-end rifle) and a higher end Spike's Tactical with all the marketing points like CHF chrome-lined barrel, chrome-lined M16 BCG, DD FF Rail, MP tested, mil-spec blah, blah, blah and honestly I can't tell the difference between the two when actually using them. They both go bang every time I pull the trigger and both exhibit the same level of accuracy (I'm sure I the limiting factor in the equation).

I think Circuits is right that most of the cost is in the name and generally with the name you get more attention to detail. I think my Spike's rifle has a slightly better over-all finish. Think Vette vs Ferrari. Both are stupid fast but the Ferrari is generally going to be a work of art inside and out.

For a professional operator who's going to use his rifle hard I'm fairly certain all those little touches and upgrades offered by the higher-end brands are very meaningful. But to a normal guy like me, I'll never notice or need that difference for the most part.