Cost, ease of use, speed, other good features, etc.
ProtonVPN also provides Wireguard config files if you don’t want to use their shitty python based GUI. Supports port forwarding aswell, althought it sucks to set up and requires to manually disable ipv6 support
I created a simple script to automatically request a port to ProtonVPN servers and assign it to qbittorrent:
Thank you, luckily arch-qbittorrentvpn already does those things, so I don’t have to