What is the preferred cartrige mm or mc and why

We just have a loading strip on our preamps so you can install anything you want (quite often with MM cartridges, a capacitance is also involved).

Quad had something similar with their earlier pre amps, with removable input boards for cartridges, and tailored boards for many well known cartridges of the day. The tape input board had adjustable settings for sensitivity, and I still use that to avoid clipping on the input by my Chromecast Audio. Peter Walker was a very practical designer.

@atmasphere Right, i use JLTi phono stage for the same reason with a bunch of different RCA plugs resistors. I just asked the designer of JLTi to change internal resistors to 500k Ohm, so i can load it down with parallel RCA plugs resistors to whatever loading value i want. I can do the same for MC cartridges with this phono stage.

On the other phono stages i just replaced 47k to 100k Ohm (Vishay Naked Foil) and it’s better for most of my MM carts.

MC because it sounds much better done right.I had MM 50 years ago then it was great but sadly its heyday is over.

Dear @atmasphere : """  the loading is there for the benefit of the phono section, which is unstable *if* the loading is a requirement. Other, stable, phono sections with the same cartridge won't need the loading to sound right.... """

Things are that some people read and read and read what you posted about ( I posted too. ) and never learn and follow speaking of SUTs with loading options for the cartridges. I have to say that some  are at the " stupidity border ".

Only a few phonolinepreamps handles the LOMC right.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.