Forcepoint could make the interface more reasonable and easier to navigate. If you are not good at Forcepoint, you cannot easily manage it. Fortinet is easy to navigate and reach.
Forcepoint should focus on upgrades. Sometimes, service is impacted or disrupted after an upgrade. You have to read the release notes carefully before doing anything.
I have been using Forcepoint Next Generation Firewall for three years.
Four years ago, I called support. Their response was very bad, but the antivirus was good.
Fortinet is better because it is very easy to manage. For Forcepoint, you need someone to dive into GUI or make some changes in the configuration, navigate, etc.
The initial setup is complex with the NG firewall compared to Fortinet. You can manage it easily by doing some virtual context and trying to divide the solution. You need experience for that. You have to do some lab to do something to prepare.
The product is not expensive.
I recommend Fortinet. Fortinet is booming now, but it is expensive. Both have pros and cons. You can compare both with Palo Alto. Palo Alto is more stable and more scalable. Forcepoint has many more features than Fortinet.
Overall, I rate the solution a six out of ten.