For most VPN companies, you basically have to blindly trust them that they aren't doing anything nefarious. ProtonVPN is different because it's been thoroughly checked and vetted by Mozilla (https://blog.mozilla.org/futurereleases/2018/10/22/testing-n...) and also because there is full transparency regarding who runs the service. You can find the names of the former CERN scientists who created the service, along with their past scientific publications, and things that prove who they are.
For most VPN companies, you basically have to blindly trust them that they aren't doing anything nefarious. ProtonVPN is different because it's been thoroughly checked and vetted by Mozilla (https://blog.mozilla.org/futurereleases/2018/10/22/testing-n...) and also because there is full transparency regarding who runs the service. You can find the names of the former CERN scientists who created the service, along with their past scientific publications, and things that prove who they are.