The reference to 'branches' in the original question made me think of a retail environment.

Some years ago, I worked on a system with a similar configuration - based on NSB's Connected Retailer product. The in-store terminals each had a copy of MSDE, and custom replication was used to return transaction data to the central servers for processing. With 500 stores in many different countries, the licencing costs of Standard Edition would have been ruinous!

We did look at replacing the MSDE instances with SQL Server Express Edition, but the lack of SQL Server Agent, together with the other limitations of that edition made it unattractive. I haven't used Compact in a production environment, but it does seem to be a closer match to MSDE in many respects, and doesn't have the CPU and memory limitations - see SQL Server 2008 Editions

Paul