带.Net应用程序的MySql或MS Sql Server

I'm developing a software using .Net platform. I want to know is it better to use MySql instead of MS Sql Server Express or not? My concern is the DBMS integration with ADO.NET and Entity Framework. Of course I don't want to rewrite the codes which Microsoft has written for integrating MS SQL Server and .Net and also ease of use(I mean wizards and ...) The program has at last 2 or 3 users but it should transfer data to a Server running Linux, Apache and MySql, So if I choose to use MS Sql Server in my application, I should transfer data between these two DBMSesI'm developing a software using .Net platform.