My 2 cents: I run Reviewable (https://reviewable.io https://reviewable.io), a reasonably successful app for GitHub. It precedes Marketplace so I handle billin

My 2 cents: I run Reviewable (https://reviewable.io https://reviewable.io), a reasonably successful app for GitHub. It precedes Marketplace so I handle billing directly with Stripe, but when Marketplace recently reduced their fees to 5% I looked into migrating there. The lack of developer control over subscriptions and the painfully long turnaround times with support to get some straightforward questions answered (3+ months!) convinced me that they're not serious about it. Anecdotally, I also heard that the discoverability boost from being listed on Marketplace isn't that big either. Based on my research I wouldn't recommend using GitHub Marketplace in its current state.