I USE Netgate pfSense for home networks, lab environments, and R&D. In production, professional career-wise, I have built pfSense production firewalls that run in various configurations and high availability for different organizations serving a different number of clients and servicing any amount of requests throughout any given day.
It also serves thousands to tens of millions of requests a second a day from small to large deployments.
Netgate pfSense is an extremely flexible solution. It is an open-source tool that has a very large community of professionals, enthusiasts, and hobbyists alike. There is a lot of flexibility in doing whatever you want with it. It also offers enterprise-grade support so that you can have something equivalent to the Cisco enterprise-grade data center firewall product. You could build that with pfSense or OpenSense, which is a derivative of pfSense.
The initial benefit I saw of pfSense was way before I ever used it professionally. It is a robust tool that can replace your consumer-grade firewall router solution. I also saw immediate benefits in my professional career as it is a powerful solution that can be compared to other solutions like Palo Alto or Meraki today.
Netgate pfSense can be a fully functional L7 firewall. You can not only have the base Layer 3 functionality of the firewall, but you can add things like Snort and pfBlockerNG to build out and become an L7 firewall doing actual inspection and security analysis.
It is very easy to add and configure features to Netgate pfSense.
pfSense has a built-in auto-configuration backup. While that is technically data loss from the sense of protecting the firewall, it is a feature Netgate offers to every pfSense user, licensed or not. You get this feature if you have a Netgate appliance. Just using pfSense won't get you that. There are third-party packages you can use to set up pfSense configuration backups if you don't have pfSense Plus.
In terms of data loss outside of that, you configure it in a way that puts it as a security device. By default, pfSense is not inherently a security device. It is a Layer 3 filtering firewall. If you want it to be a security appliance beyond basic TCP/IP Layer 3 filtering, you can run Snort or pfBlockerNG to turn it into a security appliance. Doing so can aid in data loss prevention by using the tool for basic intrusion detection prevention.
Netgate pfSense provides a single-pane-of-glass management capability. Its dashboard has a lot of prebuilt functionality, allowing you to have a single-page view of the firewall's status and everything going on with it.
pfSense Plus provides features that help us minimize downtime as a supporting part of the infrastructure.
pfSense Plus provides visibility that enables us to make data-driven decisions. The kind of data-driven decisions that could be made with information from pfSense are things like how much bandwidth I am using and what is the throughput of all my band connectivity.
I can also decide whether I need to go from a 1 Gig network to a 10 Gig network or a 2.5 Gig network and whether I need to increase my commit for my WAN circuit because we see that we are averaging above 99%, etc. The kind of decisions that it can help you make are related to your network and your connectivity.
The visibility that pfSense Plus provides helps us to optimize performance. It could help you to improve performance on the network side. It is, after all, a firewall router, so it is a network piece of equipment. It could help improve performance in that if you are actively monitoring, pulling data from pfSense, or actively reviewing the different types of information and graphs that pfSense provides, you could make decisions to see that a machine is consistently using lots of network traffic.
I have been using Netgate pfSense for 15 years.
I have pfSense Plus in production. I have both pfSense Plus and pfSense Community Edition (CE) running at home. They are essentially the same, and the only difference between them is the support and auto-configuration backup.
Overall, I rate the solution a nine out of ten.