Edward,
YOU brought all of these things up.
Not me.
-I'm rather glad that our 'debate' is ended, none the less.
Anyhow Bubba, there you go. Feel free to use whatever EQs you fancy, but -as Fletcher and I suggested, the upshot is that various different EQ types will indeed frequently produce a different sonic result, even at the same empirically observed settings.
It's an interesting subject, and one which I would have liked to research a little deeper... one day I possibly will.
Barkley, a mutual friend of ours has been known to use AR-18's in the past, right around the period when he was producing some of the most astonishing (not to mention successful and critically applauded) albums back in the early 1980's.
Another well-regarded producer these days used to always use his AR-16s (taller, deeper but about the same width) for mixing, and had me renew the drive units, also in the early 1980's. -Last I heard of him was when Terry and he were producing projects in adjacent studio rooms for a few weeks, a couple of months ago.
But as regards EQ, passive topologies will sound different to active, inductor/capacitor will sound different to capacitor/gyrator, and even within the same topology, -state variable as an example- the Amek M2500/M3000/G2520 EQ sounds dramatically different from the Neve V-series for example.
Sadly it's not really all that easy to say that one is always going to be good and another one will be bad for any given purpose... though I will say that we have a handful of CP-10's here and I typically use them on room EQ.
We've also installed a few of the Rupert-Neve-designed Summit Audio EQ's in two rooms for slight monitor response 'massaging', and people seem to enjoy those, even though it wasn't what they were designed for, and overlooking their RIGHTEOUS price tag!
The GMLs are very handy for surgical stuff on a dub stage, I know that... I hear that people do enjoy them for dialog fixing more than for musical sweetening, though I don't use them myself these days. -When I've tried them in the past, I've always noticed the noise floor a little too much to give them any serious consideration for overall EQ duties, be that program or monitor treatment.
Keith