My local audio dealer says the X993 has the best output from CD source vs. any other brands or models. However, I really like my CDA-9887 with all the DSP options.
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It provides:
Time Alignment(T/A)
R/L 3-way active crossover with volume control (all 6 channels maintain independent output levels)
5 band Parametric EQ or 7 band Graphic EQ
MediaXpander (attempts to fill out compressed music)
Sub Phase 0 or 180
Full iPod control -- check versions tho
Internal amp or played as Dead Head
4v pre-outs (doesn't seem to matter these days)
Sub system to help fill out bass at low volumes
etc...i.e. MultEQ
It's basically designed as a H/U for sq enthusiasts. Most people have no idea what to do with all of its capability. It's being phased out here in the spring so you should find some decent deals. I grabbed one for $250 shipped. This unit competes against the pioneer P800PRS and I suppose that Kenwood Excelon. I haven't messed with the X693 but the X993 was pretty nice. Just too flashy for me. Any decent SQ oriented deck will have majority of these DSP capabilities built in.
The big negative against the 9887 is that the EQ is not R/L independent only R=L. It's also limited in bands. The PEQ is extremely nice but it's only in 1/3rd octave steps. The P800PRS has a 15 band R/L EQ built in but it's crossover capability isn't as flexible. i.e. 9887 will not allow you to go very low on the tweeter HP to try and keep you from damaging your speaker, but it will allow you to over ride that safety if needed.
Sum it up....
Pros:
Cross-over flexbility
Full speed iPod controls(typically considered better than most decks)
DSP
Cons:
EQ
No motorized face