As I'am working on NHibernate and discovering some specific behaviour that increase the complexity of the tool...I just wanted to have a look on the different tools that can cover the same type of features in the .NET world.

First, I just want to creat a first list and then take the time to compare the most important features to report a benchmark.

So the most known and powerful tool is basically supposed to be NHIBERNATE if we are considering that is it an OPEN SOURCE tool !

A well appreciated tool from the commercial world is LLBLGEN PRO. Very interesting and working well but harder to use in a big project context due to the configuration file hard to share and merge (binary format).

I will have a look on these 2 tools but want to extend it to : MINDSCAPE LIGHTSPEED, SUBSONIC... and some other I suppose, if it makes sense !

The last word for now is : if your working on a medium project and you are able to manage a way of sharing the LLBLGEN configuration... this tool is a very good tool !

If you are not afraid of complex configuration and spending time for understanding and testing the generated  SQL queries and want a free tool...NHibernate is a very good tool :)