I think your looking at two very different guitars here. I own a Epi standard, and have had a lot of time with my friend's studio. My standard played better than his studio, but I think he may have had still a factory setup on it. Definitely the Gibson sounded better with its stock pups. I remember much more clear highs and midrange, while my Epi sounded kinda unclear up in the high end. I do like having the binding on my epi better, and I remember the finish on the Gibson could of been better. Also hardware was better on the Gibson with the exception of the tuners. I liked the cheaper grovers on the Epi in my opinion, they do there job well. Another thing I remember is that the Gibson had a different neck... I believe it was a bit larger than the Epi.
I think in the end if you do some upgrades to the Epi(replace the bridge, make sure it has a well cut nut, electronics upgrade, pups upgraded) it can hang on the Studios level.. I know theres different debates about this, but I think probably some would agree.. I would just play before you buy though because I've played a ton of crap setup stock Epi Standards, and Studios, and think its a major crapshoot. Good Luck!