CentOS - May 2007 - OT: InstantOgo and Zimbra comparison in Centos

Does anyone have a link for a recent comparison between groupware servers?
It's for a 1000 user deployment and I was looking at instantogo and zimbra.

thanks,


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Erick Perez
Panama Sistemas
Integradores de Telefonia IP y Soluciones Para Centros de Datos
Panama, Republica de Panama
Cel Panama. +(507) 6694-4780
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