I have used it for about 3 years. Has been working fine so far. I specifically love their registration process. If you want an account, they just give you a number and that is your only piece of ID for them. The whole process takes seconds. You can set it up in a way where mullvad only knows your IP and browser. No E-Mail address or credit card needed.

Payment is done as a credit system. You give them money and the VPN runs until that money runs out. It costs 5€ per month and the payment methods reach from PayPal to Bitcoin to literally sending them physical money via physical mail. There is no subscription of any kind. It cannot auto renew.

If you don't trust their client you can also just use any WireGuard client you want.

Definetly a recommend from me.