Zimbra will give you All Solutions in 1 Package with 1 Install. So i dont need spend hours patching up all the required components to work they way i want and in the end i dont have the Cool Web Interface i need.
Migrating to Zimbra is personal choice..
We will move 20,000 email users from our hosting platform to Zimbra once we ready and Zimbra is stable..not a big hassel..just do it right and you will reap the benifits of zimbra..
i dont work at Zimbra....lol...and again its personal choice what works for you and what you know...cheers
Raj S Vrach