The epiphone felt nice to me too.
My SG walked away one night a few years back, so I tried out a bunch of guits and ended up with another SG.
The difference, WebCyan, it what the instruments are made of. Electrical components and wood being the two main ones, not to mention the physical characteristics.
The weight comes mostly from a tighter grain wood. A wood such as Mohogany has very tight grains giving it more soild wood to resonate the sound, even though it's electric. A wood with wider grains doesn't carry the sound through it as well due to the softer spacings between the grains.
Yes, there is a difference.
Like recording, you have to know what your hearing. There is a recent post about that here somewhere.
If you can afford it, go with the Gibson, you'll like it a lot more a few years down the road. A fine guitar is just that. A lesser guitar is that.
But on the other hand, the Epiphone has a decent sound. I'm not knocking them.
I'll knock them now.
The old Epiphones have it hands down over the newer ones.
The general opinion, out and about, is that the quality of Gibson Guitars has diminished over the past ten years or so. Cost cutting due to competive pricing has been the main problem with Gibson. The quality is affected then. The SG that walked away from me was a 72 model. The one I have now is a 99. There is a difference in them. I can tell. But the average listener doesn't.
Variable after variable. The optinions are endless.
Good luck WebCyan, and long may you play.