I've played quite a few Gibsons and a TON of epiphones, and the QC on each is about the same... always try before you buy!
If you can find an excellent sounding, feeling, and playing Epiphone LP and replace the important bits, though, I think you'll easily have something that is 99-100% of a good Gibson.
Honestly, my Epi Korina Explorer smokes any real Gibson Explorer I've ever played... and it's totally stock.