OpenBase works nicely with CFMX -- at least in the developer environment.
OpenBase has a very nice GUI for managing the database.
The OpenBase develper community:
is quite a good forum, and it is monitored by very talented and responsive OB personnel.
When I first interfaced CFMX with OB, I encountered a problem in the way that the OB JDBC driver returned column names from a query.
I posted the problem to the OB list, got immediate response from OB personnel, and within days had an updated version of OB that resolved the problem.
Now, That's responsive.
I don't have the answer to "how does openbase stack up to the other rdbm".
But, I suggest you join the OB forum and post the question -- you'll get some good information!