As the title says. I find proofpoint (despite their recent security issue…) still filters email overall better than the built in offering by 365 when you have BP licensing. Never used mimecast, but curious what other people’s opinions are in the matter. For context I use both 365 and proofpoint.
Depends on the customer. Some use the built in, some use cloud, we even have one that pulls the email from 365 shoves it through a filtering appliance in their DC before being returned to 365.