Free to use and distribute
Supports desktops and mobile devices
Small footprint for easy deployment
Fully embeddable architecture
No administration required
Single file, code-free database format
Support for ClickOnce, XCopy, MSI, CAB, and non-admin embedded installation options
Supports all Microsoft Windows embedded, mobile, desktop, and server operating systems
Supports a rich subset of Transact-SQL syntax and SQL Server data types
Microsoft Visual Studio 2008 integration
Supports ADO.NET, LINQ to SQL, LINQ to Entities, and the ADO.NET Entity Framework
Supports multiple concurrent local connections