A whole lot of low-output MC’s like to be loaded 100 ohms or less in conjunction with many active MC phono stages. If you get one of those, the new additional settings at 200+ won’t help you anyways. Of course there are exceptions, e.g. Benz Ruby. And if you go with medium/high output MC’s, the 100 ohms will probably be very sub-optimal. For the most part you should be good with MC’s in the output range of say 0.4 mV and lower, depending on the gain and signal/noise of your card (the higher these are, the lower you can go, down to say 0.2 mV or less). And this range is generally considered to be the highest quality for MC carts (lower output is better as long as you don’t need the extra signal). For example, all Koetsus and upper-range Ortofons (Cadenza and up) should be an excellent match at 100 ohms.
If your phono card has an MM mode you can additionally consider using a Step-Up Transformer in conjunction with a low-output MC, at which point the cartridge/SUT pairing is the important one to match.
If your phono card has an MM mode you can additionally consider using a Step-Up Transformer in conjunction with a low-output MC, at which point the cartridge/SUT pairing is the important one to match.