Revolver Office for Mac is an office suite that includes an email client, organizer, customer manager, project planner and order-processing tool.
It's designed for use by individuals or teams of up to 100 users. Revolver Office was developed originally in Germany as was only available in German originally but is now in English. However, some of the documentation accompanying it has been badly translated in places so you may have problems understanding certain aspects of the suite.
Revolver Office offers a few other interesting features, such as an encrypted database should your information become compromised and a simple to setup and manage client server with automatic server recognition.
However, Revolver Office charges a monthly fee for those working in teams although there is a an individual license called Revolver Solo for those that just want to use it for personal use. For big organizations though, this could be a major issue.
Revolver Office is aimed at large organizations although hasn't seen much development in recent years and the monthly user fee will put many off.