I use the Pioneer just for DVD-A and SACD and it sounds great, but I have nothing to compare it to. I do not use it for video as the picture looked a little grainy to me. I am using the Panasonic RP62 for video, it has an "A" in the serial number, so that means it has the Faroudja / DCDi deinterlacing chip.
Receiver: Marantz SR7300
DVD Audio/SACD: Pioneer DV-563AS
DVD Player: Panasonic DVD-RP62K
CD Changer: Sony DVP-C650D
TV: Mitsubishi WS-48511
Sat: Echcostar HD 6000U
Remote: Sony AV3000
Cables: Monster and Acoustic Research
Center: CSW Center Stage
Fronts: CSW Tower II (Bi-wired)
Rears: CSW Surround 5.1
Back Center: CSW Newton MC300
Sub: JBL PB-10
Speacker Wire: CSW 16 ga. white
I have the DV6400 and I love it. And it does upsample CDs to (I think) 24bit/192khz. Definitely upsamples them, anyway, just not positive those are the right numbers and I'm too lazy to dig out the manual. I use it primarily for CD listening and it's vastly better than anything else I've ever owned, but that list is pretty small and all cheaper than the Marantz. Admittedly, I did no comparison shopping. I don't live within 75 miles of a dealer that carries anything but the "Circuit City" style stuff. No, I'm not bashing Circuit City, I shop there too. But their stock is definitely not shunted toward the audio lovers, though you will find the occassional gem.
Anyway, at first I loved the thing, but the transport was LOUD. You may see I posted a question about this. I talked to the on-line dealer and they were, shall we say, not up on their tech service. But then I called Marantz direct and spoke to a tech and he said it was definitely defective. So off to the "local" Marantz dealer to have it shipped back to Marantz and voila! Problem solved. So the customer service is good if you should happen to have a problem.
If it's any help, Sound &Vision absolutely gushed over it in the April '04 issue.