Monthly subscription or lifetime deal?

It seems like there’s a growing trend, especially in the indie/dev community, to move away from subscription models. In a recent thread we posted about the "ideal email client," over 160+ comments came in, and a lot of people expressed interest in lifetime deal options instead of ongoing subscriptions.

Indie devs like Marc Lou talk about this regularly. As we're building our own email client, it’s a big question for us too: