FortiGuard Web Filtering Service is well-suited for an organisation that is able to funnel all its Internet connectivity through one device, i.e., the office environment - or perhaps where WFH workers are using a remote desktop or VPN. It allows management/IT to minimise risk by blocking websites that may be harmful, as well as websites that may enable data leakage, or even are websites that people ought not to be visiting in the workplace.
We have not looked at other web filtering solutions. We use the FortiGuard Web Filtering Service as a part of the whole UTM yearly subscription that includes AppControl, IPS/IDS among other features