Mimecast is listed under Email security by Mimecast. The 3 alternatives below are listed in the same category and are compared on starting price, features and reviews from other MSPs.
Updated .
Proofpoint Essentials Email security for small and mid-sized businesses from an enterprise security vendor. 
KnowBe4 Phishing simulation and security awareness training with a large content library. 
Avanan Check Point's API-based email security that sits inside Microsoft 365 or Google Workspace. | Feature | Mimecast | Proofpoint Essentials | KnowBe4 | Avanan |
|---|---|---|---|---|
| Phishing and malware filtering | yes | yes | unknown | yes |
| Spoofing and impersonation protection | unknown | unknown | unknown | yes |
| Email continuity | yes | yes | unknown | unknown |
| Archiving | yes | yes | unknown | unknown |
| Security awareness training bundle | yes | yes | unknown | unknown |
| API-based post-delivery scanning | unknown | unknown | unknown | yes |
| DMARC monitoring | unknown | unknown | unknown | unknown |
| Attachment sandboxing | unknown | unknown | unknown | unknown |
| Data loss prevention | unknown | unknown | unknown | unknown |
| Email encryption | unknown | unknown | unknown | unknown |
| Microsoft 365 integration | yes | yes | unknown | yes |
| Self-service quarantine | unknown | unknown | unknown | unknown |
Proofpoint Essentials, which matches 5 of the 5 features Mimecast supports.
