What is the difference between DreamSpark SQL Server Express versions?
There is a info page .
It is the database plus some tools to help with maintenance in SQL Server Express, LocalDB, and SQL Azure.
Only the SQL Server administration tools but not the database.
This is a different version that is not installable. It is called directly by the application without having to install (it does not run as a service). It is lighter and a bit more limited (it does not have filestream , replication and does not allow remote connection). It does not include administration tools.
The most comprehensive, Reporting Services, Full Text Search and other components.