Object Relational Mapping Tools

I'd like to hear personal experiences about object-relational mapping tools. I've used TopLink through a third party application. Seems to me that it lacks some features and the object model is quite messy. But this is an older version and the third party people may not have used it properly.

I've read about CocoBase, but have no personal experience using it.

Both products seem quite expensive. That's why I'm rather interested in hearing about open source tools in this area. Or inexpensive ones.

Thanks.

GaryZuo

See the Cetus Links page on object-relational mapping at http://www.cetus-links.org/oo_db_systems_3.html.

See also: TopLinkForJavaUsageExperiences

I have had success with HiberNate -- ZhonJohansen