My friend has Sota comet with RB 300 tonearm and Grado Gold prestige cartridge. He used the setup for a while, but he was not satisfied. After consulting with a seller of the table, he changed to Goldring Electra cartridge, a cheaper one. But he likes it better.
IMHO, Sumiko Blue point special MC cartrigde is one of the best at under $500.
IMHO, Sumiko Blue point special MC cartrigde is one of the best at under $500.