I use to sell a lot of Audio Technica OC9's which worked particularly well with the Rega arms.
The early Rega moving coils for me we're a bit "hard" sounding - partly I suspect because they had unusual impedance requirements and really sounded best with the Rega phono which used input transformers matched to the cartridge.
However I know someone who has run Shelters & Benz's with the Rega arms with good results and has just taken delivery of the top 2 Rega MC cartridges and is really impressed - they are way better than the older models and ahead of the Benz/Shelter's
Since VTA is not adjustable easily on the Rega arms going with the latest Rega MC's has a big advantage with ease of set up.