<p>I have seen the references to VistaDB over the years and with tools like SQLite, Firebird, MS SQL et. al. I have never had a reason to consider it.</p>

<p>What are the benefits of paying for VistaDB vs using another technology?  Things I have thought of:<br>
1. Compact Framework Support.  SQLite+MSSQL support the CF.<br>
2. Need migration path to a 'more robust' system.  Firebird+MSSQL.<br>
3. Need more advanced features such as triggers. Firebird+MSSQL  </p>

Well, the main thing is that it is pure managed code - for what that is worth; it works not only on your typical Windows machines running .NET, but works wherever you run the Compact Framework and even works on
Mono
. Here are some noteworthy bullet points from their homepage:
Small < 1 MB footprint truly embedded ZeroClick
Microsoft SQL Server 2005 compatible data types and T-SQL syntax
None of the SQL CE limits
Single user, multi user local or using shared network.
Partially trusted shared hosting is no problem.
Royalty-free distribution - single CPU deployment of SQL Server costs more than a site license of VistaDB!
One thing worth noting is that Rob Howard's company,
telligent
, uses it as the default database for their new CMS software, "
Graffiti
."
I have played with it here and there but have yet to build anything against it.