Hi Robert, The Classical advanced search doesn't work as well as we would like.
Many classical crossover albums (recordings with both a classical audience and a popular music audience) have dual sets of information in our database. Our data provider often puts more emphasis on the "Pop" entries (even for things that are tagged with Classical) so that is why the results often skew to seem more pop (for example: Billy Joel or Chick Corea's classical works often show up above more traditionally classical recordings). Filtering by editorial star ratings also seem to cause entries to disappear for an unknown reason.
It is something we are aware of and are working with our data provider to refine.
If you can provide specific examples of what you were looking for (and where it failed) I can maybe offer tips to help you.