It's an enterprise AV for servers (mail servers for example). It's not bad, but from my experience lots of fp's.
Fortinet products are not primarily designed for home users, it's mainly designed for (very) large corporate netwok. Fortinet FortiGate Antivirus Firewall (hardware) is a very good product, it's extremely fast and effective with very high traffic throughput but Fortinet seems to mainly focus on detecting dangerous malware that are really spreading in the real world so its overall detection rates (zoo malware) are rather low but that's not a big problem, Fortinet still detects what it should detect timely.