I recently bought the Pioneer Bluray and still retained my existing Pioneer DAV-600 DVD player, both feeding into Pioneer 428XD plasma. The DVD performance is slightly better with the more expensive Bluray player which cost 6x more !!!! ....but here's where I may cause a stir. With all the news of upscaling DVDs being all the rage, to my eyes at least, I actually get a better picture just setting both the bluray and DVD players to standard source direct output resolution i.e. 480i/p or 576i/p depending on DVD disc rather than 720p/1080i/1080p which all my other friends rave about. Perhaps it is the 428XD plasma which is a better upscaler when fed a standard def feed.
Personally, however, I still think I spent too much on the Pioneer bluray but after watching some demos, I was blown away.....but as you said, if money was no object, you just have to buy the pioneer bluray. It's up to you then whether to use the upscaling function or not.