I own the CX-7, upgraded to "e" series, then to "MP" series. Never directly compared them, but I have heard a few iterations of all three Ayre players. The D-1 is a top-notch CD player - and also plays DVDs, of course. I would guess the C-5 is probably just a bit better and the CX-7 just a bit less. See Shane Buettner's review for his thoughts comparing the C-5 and D-1. With the MP filter, I would hazard to guess that the CX-7 is a "better" (i.e., more musical) player than the D-1, which was discontinued before the MP filter became available. I think you can be happy with any of the Ayre players (never heard an Esoteric), but a C-5 MP is probably the best sonically. If you go for the D-1, make sure to get the "e" series (you can send an older unit to the factory for the upgrade).