The feature of Cisco Secure Firewall I prefer most is troubleshooting, packet capture, and packet tracer; I love those features.
You can quickly run certain commands on CLI or on FMC CLI to find out what could be the root cause, and it varies from person to person, but it's very useful.
I prefer Cisco since it has been here for a very long time, we have a good relationship with the sales team and Cisco representatives, and the support is pretty good, providing us with 24/7 support, which makes me pretty happy.
Cisco Secure Firewall in helping my company implement a zero-trust security model. I've yet to try it, however, I'm very excited to work on it. My impression of the visibility and control capabilities of Cisco Secure Firewall in managing encrypted traffic is pretty good. We can build site-to-site tunnels and various ways of site-to-route based or policy-based, allowing us to see the packets and cap decaps, and Cisco CLI provides a way to see the packets inside, which is very helpful.