I’m moving to eForm from formail.php. Two of the things that I really need are: logging form results to a CSV and the ability to grab the HTTP_REFERER and report that in results.
To do this you need to use the eForm events and use a php function to get the refferef and then to write to the CSV (or to a database). Take a look at eForm2db to see this in action and look in the eForm documentation (assets/snippets/eform/docs) for more information on using events.