CD player or Transport and DAC

You're probably not making a valid comparison in your example. Rather, compare a $4500. single box CD player with a set of separates that also cost about $4500. together. Afterall, a single box CD player also contains a DAC (built in). In this case, and depending on a lot of variables, the single box player MAY (musically) out perform the two box system just because of probable designed and built in synergy between the transport section and the DAC section. However, I have chosen the 2 box route for the CD player's many features and for DAC flexibility, ie I have 2 CD players and a CD recorder plugged into my DAC.

One could have a religious argument over two boxes versus one and get nowhere. There are trade-offs involved in each design but there are other more significant sources of the differences in sound you encounter with CD players. I reckon you should rule out neither and audition anything in your price range - whether one box or two. If you are really spoilt for choice, Garfish is right to imply the one box player makes things simpler - a good thing.

Your buying decision should also take into account the availablity and possible cost to bring your front end up to the new standard(s) should a concensus ever be agreed upon. Of course if your interests are only in 16/44 CDs then the above will not apply.