The full version of db4o is available under two licenses (dual license): the open source, GPL, which enables easy download, evaluation, and use in GPL compliant projects; and a commercial runtime license with indemnification from db4objects for product development companies that wish to embed db4o into their commercial, non-GPL products.

The commercial license comes with direct support from the creators with guaranteed response times in 24 hours or less.

As you would expect, the free version only provides the usual peer support via the db40 developer community discussion forums.

When I don my architect/developer cap, I find myself particularly interested in professional tools which assist in interoperability between different platforms (IBM mainframes and mid-range systems, the various Microsoft server platforms, Sun's Solaris, and so on). I'm tickled pink by the the claims and counterclaims of their devotees, the marketing antics, the froth and bubbles, and all the fun and games played out on both the sales/marketing and the technology stages!
 

BUT GETTING SERIOUS, PLEASE READ ON...