What is the difference in reward between praying in a mosque and praying in a zawiya?

The worshiper receives the reward of congregational prayer whether he performs it in a large or small mosque. However, praying in a mosque with a larger congregation is more preferable, as the Prophet, peace and blessings be upon him, said: "A man's prayer with another man is purer than his praying alone, and a man's prayer with two men is purer than his praying with one man. And the more numerous the congregation, the more beloved it is to Allah Almighty."