Database Engine which is compatible with on-premise and cloud release.

The most valuable feature of LocalDBis the connection between the application and DB.

The solution is fast.

We are able to integrate easily with the Active Directory.

The memory footprint is the smallest in its category of products. I think Microsoft did a very good job squeezing as many features as possible in such a tiny executable. The price, being it free, it's of course a plus. And the capability to do almost everything as in the commercial version. When using a developer machine or also a virtual machine, it is essential that every MB of memory is well utilized. The binaries are loaded in memory only when needed. It uses the same client libraries as its bigger siblings, including the Native client. Unlike the Compact version which uses a limited set of functionality this LocalDB has Stored Procedures, Geometry, Geography data types, online backup, transactions, data integrity etc. It runs as a separate process as opposed to in-proc DLL.

The solution has powerful reporting features that are very valuable. The user interface is the standard SQL management tool, so it's very easy to navigate.