What cartridges have you tried with the MH MMF7?

I have used a Goldring 1042. I am now using a ZYX Airy 3 with the Cartridge Maker's Isolater. Loads of detail. However good cables are a must. I am using Harmonic Tech's. Good luck.

I am thinking about a Shelter 501 mk2 for my MM7, any thoughts on this?

Well, watch out going over 8 grams... I was told up to 10 gram would be fine, but guess what I had to purchase the 90 gram heavy weight for the Project tone arm and it works just barely, and had to come from sumiko California, the only distributor for project that can get them I guess. However the lowering arm is not damped quite enough or something for the 9.5 gram cart I have on it, and it will come down pretty quick and take off a little once in a while on the blank header of the first track and jump right into the begining of the track rather quickly. This can be counteracted by simply holding onto the lever and kinda lowering by hand all the way to the surface. Beyond that The original tonearm wire is horrible in comparison to putting the cardas in it and eliminating the RCA box all together and running the wire all the way to the preamp, but this was a nightmare project.. Just from my expereance its night and day from the wire alone. I use an Ortofon Kontra B, killer cart.. big time bass(the most I have heard from any cart) and super smooth dynamics, rediculously powerful with a pretty standard 60db MC phono.

Installed a new Shelter 501 mkll. A match made in heaven for sure. So much better than the stock Goldring.