Review on db4o by Keegan Herbert

easy to integrate in any project (even mono ones), fast performance even when using many concurrent connections from multiple threads; persistence is rock solid - not one crash during all our years working together so far! very flexible schema design that allows us doing almost anything we need without having too much pain afterwards if it goes wrong ;-) there are some features missing compared eith other ORM systems like NHibernate but this doesnt really matter since they work perfectly fine otherwise :).