MM Vs MC

I am an idiot and I accidentally busted my Sumiko Blupoint Evo iii. Anyhow, I was shopping for a new cartridge and an "expert" told me that MC cartridges were only necessary on older tables with heavier tone arms and that since my tone arm is made of carbon fiber I'd do just as well with a MM cartridge. He says they will both retrieve the same amount of info from the grooves of your record. Is this true? I've always been told that MC cartridges are the higher fidelity.