They're taking a cue from WWE. Just as it has three "brands" (RAW, Smackdown, and ECW), Iovate has three types of bodybuilding supplements (MuscleTech, Six Star, and Muscle Asylum).
Six Star seems to be more of the bargain basement supplement. Their Professional Strength Protein and Creatine products are the cheaper answers to Nitro-Tech and Cell-Tech, respectively.
Six Star has a NO powder (N.O. Fury), as a counterpart to the more-costly NaNO Vapor by Muscletech.
There's even a fat-burner, Drenalin Hardcore, that looks to be the bargain version of Hydroxycut Hardcore.
Plus, Six Star products tend to be marketed more in grocery store, like Wal-Mart.