I am having quite a few problems understanding differences between regular SQL Server Express and express Localdb.
Before you go ahead and tag a previous post about this question, I've went through question history quite a few times.
The resources that I found somewhat helpful were: Is there a difference between SQL Server Express (2012) and LocalDB? and an official Microsoft page article about it.
I believe I do understand that Express Localdb is an edition of SQL Server Express, that is targeted to developers in order to reduce time consumption of all the "configuration".
What exact configuration? What is the difference If I use Username\SQLEXPRESS versus (Localdb)\MSSQLLocalDB, it creates a database anyway. What are the differences in terms of publishing your application into production?
LocalDB is a special, low impact version of the SQL Server engine, that is not installed as a Windows Service, but launched (made to run) on demand by the ADO.NET client opening a connection to it. It is intended for single user scenarios, and not for any production use - for production you should use SQL Server Express (or higher)
I have a blog post that compares the various engines here: http://erikej.blogspot.dk/2011/01/comparison-of-sql-server-compact-4-and.html