I use them in some cases to avoid the rate limits on LetsEncrypt, and they have better support for some older platforms (like ancient Android versions), and I'm pretty happy so far. I have a paid account to support them, but it's not a requirement for ACME certs. It works without issue with Kubernetes Certbot, and seamless to switch between ZeroSSL and LetsEncrypt.

I can't comment on the EU part though - not that relevant in my case.