INKY

we use it internally and for our clients. we migrated away from a tradtiional SEG that kept having outages. The system works amazing and has many other optional features as well. Its very easy to deploy for M365 clients, and although it works for google it can be a bit more difficult to deploy. MS deployment takes about 5 mins, where google takes about 45 mins.

definitely great to use for any microsoft Client, the google issues are more a google thing so you will have similar issues with any other vendor. If you do not want a SEG for google, then use INKY Behavioral Email Security Platform, as it is still great once you get it set up