I literally just switched away from Hurricane Electric to deSEC. The only real issue that I had with HE, but it's a big one, is that they don't allow wildcard CNAMEs. I consider that important for the security of some sensitive endpoints that I have no choice but to expose publicly. Those endpoints are well protected with 2FA and heavily monitored, but I wanted to be able to use randomized subdomains to at least have some obfuscation on top.