I am looking into using a lightweight serverless database engine like SQLite, Firebird, or VistaDB in an upcoming project.
Someone asked about What are the advantages of VistaDB.
I would like to know what are the disadvantages of using VistaDB versus other technology?
UPDATE: VistaDB out of business (the real disadvantage)
I have just learned that Infinite Codex (the company that owns and makes VistaDB) is going out of business and the offices will close as of August 1, 2010. View the company press release regarding the closing.