Hello,
One of the non-profits I consult recently received a used Fortigate 50B from a donor. The company is also looking for a new software AV solution, since they were using an older unsupported version of Symantec Endpoint and it wasn't working too well. I usually recommend Avast as a software AV, but the Fortigate adds a new possibility.
My preference is to skip the possible headaches with installation and just implement a new software AV, but it's hard to ignore getting a hardware firewall/AV device for free. Is it worth it to skip the software solution and just renew the Fortigate support contract? It would save the company about $150/year compared to Avast packages with comparable features (AV, Anti-spam, web-filtering, etc).