I use the one from my ISP, unless they're having issues (hardly ever happens). The reason for this, is that in my country, my ISP is tied to strict regulations

I use the one from my ISP, unless they're having issues (hardly ever happens). The reason for this, is that in my country, my ISP is tied to strict regulations on (for example) resale of data. Switching to another DNS provider opens me up to all kinds of shenanigans that my ISP would be held responsible for. This is the same reason I don't use a VPN by default at home.