@aminb .cz because:
• general use is allowed
• its community maintains free and open source projects¹
• were quick with DNSSEC introduction and pushes for more²
• they create open hardware projects³
I did not find any other domain operator that is so transparent and use funds to do useful stuff, so currently I give money to them.
¹ https://www.knot-resolver.cz/development/
² https://en.blog.nic.cz/2018/06/01/transition-to-elliptic-curves-in-the-cz-domain/
³ https://www.indiegogo.com/projects/turris-mox-modular-open-source-router-security-computers#/