I believe the 630 is going for like $400 or so and the 635 is like $650. In that price range you might want to take a look at the Denon 1905, 2105, the onkyo 602, 702. and the marantz 5500. You can get a refurbished Marantz 7300 from an authrized dealer for $600. Just tossing those up. Really depends if you care for the DSP and stuff.