I noticed 30,000 failed charges in one year. I'm not sure if that's interactive failures, as in users actively trying to complete a transaction, which is much less important than the recurring failed charges, as in money you thought you were going to get but didn't, for no other reason than the payment network.
I hate seeing those failed charge notifications that go out every morning when you try to bill that day's batch for the next month of service. And then wondering how much that's pushing up your churn rate, how much effort should you spend trying to get updated billing info, etc. Buffer is mostly $10/mo, so I would imagine not much chasing is going on beyond a few automated emails... but it's enough to make you want to switch to ACH!
Does Stripe handle auto-updating credit card details when a card expires like some companies seem to be able to do? With the massive leaks lately, and so many card numbers getting cycled, it definitely hits the bottom line.