What's with all the NordVPN hate?

I see people say that NordVPN is a bad choice all the time, but I've never seen any credible evidence that they're not trustworthy. Can anyone provide any sources with valid reasons to avoid their service? I only know that they had some servers hacked in 2018, but it seems as though they took that very seriously and upgraded their hardware and encryption accordingly. I'm just trying to decide if I want to start looking at alternatives, but honestly I'm pretty satisfied with my experience so far.