I had the Naim 555 in my system for about two weeks (loan from a friend on vacation). That is a fantastic player. For substantially less, you can get a reasonably close approximation of that sound from the Naim CDS3. I own a CDS3/555PS (power supply from the 555 player) combination. Both the CDS3 and 555 are quite different from the Naim models below them in the line. They have the good dynamics expected of Naim gear, but, to me, they both sound less mechanical and artificial sounding (less of a sense of artificial "enhancement" of the leading edge of a transient). The 555 is just a bit "more" of everything than the CDS3 -- more weight and authority, slightly bigger soundstage, etc.
I have heard, in a dealer's system, the Linn CD-12. That is a sweet sounding player. I don't know how it compares to the Naim, because I have not heard it in my system.
I have also heard the Audionote DAC-5 limited DAC combined with a number of different transports and found it to be exceptionally musical, relaxed and beautiful sounding without being sluggish, murky and undynamic. Quite an amazing DAC, but the DAC alone is way more expensive than the Naim 555.
