We have one main office with 350 employees and 2 Satellite offices with each 120 and 60 employees.
They are connected thru Gigabit WAN, this link is used for many otherthings apart from Zen, like backup etc.

We propose the following setup: 2 Primary Server (PS) at HQ defined with Closests server rules (CSR) to load approx half the PC's on each PS with the other PS as #2 in the CSR's. the PS uses an external MS SQL Server for Config db.
For the remote sites we setup Satellite Servers at each site - fully configured as Content, Collection and Image servers. CSR's setup to service the PC's at those sites locally. Each with on of the HQ PS's as #2 in the CSR's
Image files are replicated by using Zen bundles from the PS location to each of the Satellite locations.

Only question: What would be Pro and Con to using Primaries at the remote sites instead of Satellites ?