I did a comparison last night and I can say with certainty that the NAD is a better sounding player. They both sound excellent and both are excellent at rendering realistic timbre. The Marantz is a bit more forward and isn't quite as refined on either the top or the bottom end. The bass is fuller with the Marantz but seems just a tad over ripe. The highs aren't quite as articulate, I can clearly hear different brands and types of cymbals with the NAD that I cannot with the Marantz. The transport is quieter in the Marantz and that is nice but as good a $350 player as it is, I could not live with it in the main rig unless my other deck was in for service.
Conclusion is that the Marantz CD5004 is a fine sounding deck which has outstanding build quality and quiet operation. It's a excellent bargain at $350.
The NAD C545BEE is an outstanding sounding player with better resolution and an more organic presentation. Everything is in it's place and sounds more live than the Marantz. Operation isn't as quiet and the transport can be noisy with some discs, not most though. I've cross checked the same discs on my wife's Rotel RCD 971 and find that the discs also make more noise with that player than the average disc, though not as much as on the NAD. The Marantz is virtually silent with every disc.
I love the sound of the NAD, now if only the transport were quiet and it didn't have the auto shut off feature:scratch2:.