Sure, Gibson has the notoriety, but Epiphone makes damn good guitars. Many people prefers Epiphones to Gibsons purely because Epiphones have certain necks that are entirely their own, in addition to many other specifications.
Many, many players even endorse Epiphone as readily as they do Gibson. When it comes to live performance, however, I've noticed that these same players rely solely on Gibson for their show.
I just think it's interesting that when it comes time to truly throw down, Gibson is the only one they go to...
I own and play both brands. Of course Gibsons are "technically" better, but I've played some Epis that just smoke. Epiphone makes a mean semi-hollow (I'm looking at you Dot!), and they are more than worth considering. To my mind, there is little difference between a high-end Epiphone and a low-end Gibson.