AR15 is the common parlance for all of the rifles that are based on the Colt AR15, even on most gun forums. Not all AR15s are created equal, however. Some of the more common brands have a lot of corner-cutting and an inferior QA process. For many people it's not a big deal because they'll never push the gun hard enough to discover its material weaknesses. I've seen many rifles fail to make it through a weekend 2000-round carbine training course and it's usually the same brands.
'04 MariStar 230VRS/MCX