What are some alternatives?
EuropeanMX - Protects your company by blocking spam and virus before they reach your network.
Vaultastic - Vaultastic is an elastic cloud email archiving platform to help you Preserve, Manage, Discover & Recover email data easily & quickly
SpamTitan - SpamTitan is an anti-spam email solution specifically developed to meet the demands of modern business. Delivering a spam detection rate over 99.9%
Aid4Mail - Aid4Mail is a software specialized in migrating a massive range of email programs, webmail services and mailbox formats etc.
Altospam - Antispam and antivirus software on Cloud
RestorEmail Archiving - RestorEmail Archiving or RestorEmail Cloud Archiving is an IT solution for Email security, protection and compliance as well as allow you to archive your business email like Office 365, Google Apps and Exchange online etc.