Per User install:
Pro
Load spread out over Multiple PC
Con
Multiple installs/maintenance
Performance decrease on Client PC during sync
Multiple database connections

Dedicated (from One PC) install:
Pro
one install/maintenance
NO performance decrease on Client PC during sync

Con
huge load from one PC,lots of memory etc... (with large number of users Multiple Dedicated PC's needed)

See also Exchange and Outlook on the same computer:
http://support.geniusconnect.com/topics/32- 



For the dedicated install (one PC) see example:
MS Exchange examples: How to synchronize multiple MS Exchange user accounts from one dedicated PC/Server with MS Outlook and GeniusConnect.
http://www.geniusconnect...es/GeniusConnect/2/3/66/ 

For the install per user see topic Automatic Deployment:
http://support.geniusconnect.com/Posts/t140-