The main difference is customers will send the BTC a few minutes too late, and then it turns into this situation where it has to be refunded. This used to be an extra step when using Stripe for BTC payments (they have since stopped supporting BTC payments completely)
It was PIA - PrivateInternetAccess. I first tried ExpressVPN and for privacy I'd recommend ExpressVPN because they located in a place with no data retention laws. However PIA has port forwarding support and that is crucial for my case.
Both support payment via Bitpay. ExpressVPN returned the money no problem after I've discovered that they don't do port forwarding.
Mullvad has been great. Very easy to setup and they do not take any of your personal details. Instead of a user/email and password, you get a random account number that is used to track your payments and authenticate you.
EDIT: s/now/no