We use AlgoSec Firewall Analyzer and AppViz. We have bought the FireFlow license, but we do not use it currently. We plan to use it, but we are not using it right now.
Firewall Analyzer is helpful for network assurance and meeting some requirements of PCI DSS.
We use it to manage only our on-prem environment. Our network environment is mostly on-prem. We do not use cloud networking. We have an internal cloud, which is hosted in the Netherlands, but it is like a private cloud.