I own the denon, and I've heard the sony. I may be a bit biased since I own the denon. . . but I'd put it pretty much equal stock, and slightly ahead when you remove the headphone jack(10 minute job), where some of its low points(highs, dark sounding), are fixed a bit (Highs less fatiguing, and mids are more neutral).
But both are fine players. . . if I had to choose, I'd go with the sony, simply because it's also an sacd player. But be advised: its a dvd player first, cd player second, so it may not be as easy to use(but personally, who cares?)
Good luck in your decision! You won't be disappointed with either one.