It's hard to tell how guitars are going to appreciate - granted, if you were looking at a rosewood from the 50's or 60's, that's a different story. The 70's models don't have the mystique that the earlier ones did.

The OMJM's are fantastic guitars, I've owned a few and if you get one setup/dialed-in to your likings, they are such a versatile guitar. Hard to beat.

If you're in the dreadnaught camp, I would HIGHLY recommend looking and playing an HD-28V. On top of the aesthetics (herringbone trim/tortoise pickguard/butterbean tuners), I've yet to play one that doesn't boom - and I've mostly played them off the wall. I can't imagine how great they'd sound with a setup and new strings.

Whatever you do, try to go play as many as you can and if you are going to buy new, check out Maury's! Enjoy