I have a Denon 3930 DVD player. It does an excellent job scaling from 480i to 1080p, with virtually no perceptible artifacts on a 60" 1080p display. It's about as good a standard def image as I've seen, outside a professional mastering suite.
Having said that, my blu ray player, which is now several years old, trounces the DVD player for picture quality. It is really no contest.
So I would say take Albert's advice and try the OPPO. But don't sell your Esoteric yet. It's possible that the Esoteric's picture quality is better on standard def DVD's. That's the reason I didn't sell my Denon DVD player. On standard def material, it is far better than my blu ray player.
Bryon