The idea that you have to match the brand of cartridge to the brand of arm is ridiculous. It is the kind of nonsense hype broadcast by Rega which sells a lot of arms and would like to sell a lot of cartridges, some of which are simply re-badged and repriced from other manufacturers. Over at AA where lots of systems are listed, most owners of Rega TTs who list their cartridges are not using Rega cartridges. Now, some of Rega's MM cartridges may be terrific. I wouldn't really know as I haven't considered MM cartridges for many years. But I have friends who have found success with Ortofons.