Hello, Thanks for your reply.
One problem with EF was its tight integration into the specific .Net framework, which is (thank to you, guys) now relaxed. OS requirements for .Net4.5 will limit our client software to migrate to 4.5 for a long time, with our server already running on 4.5.
The fluent API means that information about classes be kept apart from the classes, which for a large, ever changing project will be a maintenance burden. Data annotations is the way to go. For now, we come to the compromise of using EF assembly in our client software.
For our non-desktop clients (handhelds, for instance) we had to create client only classes and write transformation code to convert from/to server classes.