Any reason NOT to switch to ProtonVPN from Mullvad?

Is there any reason NOT to switch to ProtonVPN from Mullvad?

Use cases: privacy, torrenting without getting a DMCA letter.

OSs: Linux, Mac.

I know there was a reason I didn't pick up Proton years ago when PIA got bought by Kape but I don't remember what it was. I'd read something on /r/VPNTorrents but that place has since been banned so I can't refer to it again.