MM or MI Cartridge?

If you are unwilling or unable to seek out a Decca Super Gold, +1 Nagaoka MP500. Also look at the Audio-Technica AT150ANV if you want detail and open-window clarity. I recall Fremer giving it very high marks. The Grado and Goldring (Audionote) are pretty warm sounding by some accounts.

Moving coil cartridges do indeed have the lowest inductance of any of the three types, by far, but they also have the highest moving mass. Moving iron type cartridges have the lowest moving mass on average. MM types are somewhere in between. Therefore, any response retarding effect due to hysteresis caused by inductance is compensated for by very low moving mass in the case of the moving iron cartridge. Which may explain why the general conclusion that MC cartridges exhibit superior high end clarity, based on hysteresis alone, does not conform to my long-term observations of the performance of the three types of cartridge.

Well said, @lewm .

Forgot also to mention typical compliance numbers that might affect response time. MCs typically exhibit lowest compliance. The exceptional MCs that exhibit higher than average compliance are the ones I like best.

The big difference between MC/MI/and MM cartridges boils down to a very few factors, most notably stylus profile, of which much ink has been spilled, and inductance, which is rarely mentioned. Moving coil carts have the lowest, then Moving Iron, and then Moving Magnet. why does this matter? Inductance directly relates to a property called hysteresis, the delay between a change in input and a change in output. Google 'hysteresis curve' and you'll see the characteristic 'S' shaped hysteresis curve, and its return, the hysteresis loop. Ultra low output MCs sound fast and detailed in large because they have low inductance, thus low hysteresis. MI carts like Grado and Soundsmith  have greater inductance, roughly in the 50mH range, but the difference is incremental. Most Moving Magnet carts have 10X more inductance around 450-550 mH and accordingly 10X more hysteresis, more delay between changes in input (stylus motion) and a change in output voltage. They simply cannot respond without 'smearing'. The tradeoff in general is output voltage, where MM carts win by a mile, thus making preamp design easier and more forgiving. This is why most MC carts require an additional level of gain, and usually worse S/N ratios. There are other factors, to be sure, vibration control, compliance, tracking ability, and several more but all of those can be controlled independently of the electromagnetic performance of the generator which is determined in large by the cartridge designers choice of MC, MI, or MM. I haven't gone into cartridge loading which is important, but cannot compensate for the hysteresis inherent in the design.
 

Bunch of ill thought out hooey here!

Hysteresis refers to the coil core material ONLY. There is no hysteresis in an air core coil, or a non-magnetic core material, such as aluminum or plastic. Iron alloy *can* have hysteresis, depending on the alloy or physical form. Hysteresis results in loss of magnetic flux, but no loss in speed, as magnetic flux is transferred at the same speed of light as do electrons travel through a conductor. Resistance to electrical flow or magnetic flux may decrease energy transfer, but NEVER speed! You need to go back and study EE 101! 
 

Laminated coil core materials exhibit very little hysteresis, as used in the Shure M24, V15-III, IV, V. 
 

MI cartridges, as a subset of MM, have wide ranging inductances, as do MM carts. There is no “set” range of inductances just because a cart is MI, or MM. To say there is, displays a complete ignorance of cartridge types and design over the last 7 decades. Inductance of MM/MI carts determines output using a given magnetic flux density. Cartridge loading affects FR of a given combination of inductance and magnetic field strength. 
 

MC, or MI/MM just categorizes which comprises you choose to accept. There is no inherent superiority. Whichever you choose, choose wisely. There are so-so MC carts, and also MI and MM carts. Don’t use a broad brush, using a bad example of an MC to condemn MCs, or condemn all MMs or MI carts because you had a so-so example.