Cartridge upgrade for vintage TT - MM or MC?

The MI cartridges (moving iron - Grado/SoundSmith/B&O) are much better with far lower inductance. And consequently much better high end and faster transients. They are certainly competitive with MCs. I have several Grados. In fact back in 1977 I was one of the first to hear and use Joe Grado's new Signature 2 ($500 - gasp!). At that time the Koetsu was $1000 (double gasp!). And was superior in sound quality!

The PLX1000 has a medium mass arm. It works fine with the low-compliance Denon mc. I have other TTs with high-mass arms (Empires) that are certainly suitable for mc cartridges. Plus also two Fidelity Research arms designed by the late Ikeda-san (FR29 and FR54) expressly for MCs.

I don't believe in re-tipping. When my Denons get too worn I can trade them in for new replacements. And they can certainly go beyond 300 hours by use of Stylast. 

I have no idea how a conical tip with 2g tracking force can last more than 300-400 hrs not being worn out, elliptical can be used a bit longer, but they are all inferior compared to a proper profiles like Shibata, LineContact, MicroRidge ... that comes with MM and MI cartridges (some of them also have much better cantilevers).

I have never experienced roll-off with MM or MI from Stanton or AT top models, but i pretty much experienced a roll-off with SPU cartridges (just like oldchool Denon). MM is a choice of industry professionals, let me remind about this article again. Since they are vintage cartridges (from the 70s/80s) we can’t find much info about them, except for an old press like TAS etc.

Denon require not a Mid Mass arm, but a Superheavy mass arm like FR-64s (over 30g). So you need an iron headshell and a brick instead of the regular counterweight on your Pioneer turntable.

In fact i have Grado Signature XTZ (MI) right now on my Denon DA-401 tonearm and this particular Grado was the best from the founder of the company. And yes, the price was $750 in the 80’s. I like this cartridge, but it can’t surpass some of the very best MM from AT, Victor or Stanton.

I have submitted a technical inquiry with Fluance to have them explain their cartridge matching to me.

Maybe they just don't think resonant frequency is a big deal? The agent I spoke with said the specs are correct.