I'll have to put in my 2 cents worth about external DACs.
The "1-bit" or Bitstream DACs used in some CD players are crap IMO.
(I've also seen measurements that indicate that the output sections of some DACs may have problems driving the output filters. That's more likely to happen in a cheap CD player where they might very well toss in a 741 or other sub-par opamp.)
My preference is a standard 16-bit 4X oversampling DAC.
It's my impression that the "1-bit" DACs can be made less expensively, so I would expect to see them widely used in mass-market CD players. It could well be very difficult to find an inexpensive player with a 16-bit DAC.
Given the above, I think it's a good idea to use an external DAC and then whatever player is a good deal for use as the "transport."
This is just my opinion.
Also, note that the DAC I selected is far less expensive than the majority of the "boutique" DACs you see on the market, so I'm not saying you need to spend huge amounts of money.