Oh, yeah, I totally dig DEQ. I find that it doesn't mess with the quality of the midrange or treble at all. DEQ just makes the bass punchier, tighter, and more dynamic.
I tried an experiment where I turned DEQ off and just made the bass super hot +9dB. This caused the bass to be just boomy and muddy, not punchy, tight, and dynamic at all. But with DEQ, I get totally tight, dynamic, punchy bass.
So this tells me that DEQ doesn't just boost the bass level since manually boosting the bass level doesn't achieve the same effect.
Interesting thing is, people seem to have different results (or preferences) no matter what systems they use.
I've listened to ARC at someone else's house, and I thought DEQ sounded much better. But, of course, we are talking about 2 completely different systems.
But even if it were the same exact system, it would probably still be a matter of preference.