Over the years, I have noticed the same thing Spacealf, Gibson's hold there value pretty well. Same has been true for the Rickenbacher's and Martin's that I have bought and sold. I had a Fender American Deluxe Strat that I sold once, where I had changed out the neck with a custom shop Fender neck and the buyer complained that it was no longer original. Here I thought that was the beauty of a bolt on neck, you could replace it with a new and maybe even better one, if you wanted.
I have noticed a resurgence in ES335's over the last couple of years. I have also noticed several blues players, Bossanama (sp), Jonny Lang and even Clapton playing Paul's again.
One thing that I have done over the years as turn a good Epi into a player by changing out the pickups with Gibson Classic 57's or the likes. You can come awfully close to the real thing with a good pick up change. For me, it is still about the playability of the neck on guitars. It's which guitar, even in the same line, feels best in your hands.