What problems is Forcepoint Web Security solving and how is that benefiting you?
The Sandbox is a very useful solution for sand-boxing malware / phishing etc. from corporate email accounts. No matter whether it's on Office 365, Exchange (on-premise), or Google (or any other cloud). The Sandbox updates on a regular basis, and the flexibility of policy configuration, white-listing is pretty good.
Reports in the sand-boxing, ease of deployment of sensors to ready to go server with one click of a button.
I think there is room to improve the reporting area of the solution and also the investigation part, a basic section where you see the body and headers of each email and the reason it got blocked. Review collected by and hosted on G2.com.