One advantage of Quora's plans is that creators have more earning potential there through Spaces - which act like Patreon's membership. Creators can set the membership payment to whatever they see fit, and they get paid by their members directly.

Medium's model is indirect payment through paying members of Medium, paid for views. Which is akin to Quora+.

This system is highly skewed in favor of the highest reach creators - resulting in only ~5% of writers making over $100/month. And the rest making tiny amounts like $1-2 dollars.

Whereas 100 paying members paying $1 each at Quora Spaces will help you get to $100/month, at Medium such an amount of supporters and associated views wont get you anywhere.

So Quora's program has more strength in that regard - Medium is a highly unequal platform.