Very nice data gathering/processing

The option to alter submitted form data through functions.php is wonderful! I use it to clean up the input (strtolower etc) and to calculate a score which can immediately be outputted in the CF7 succes message. Possibilities are endless.

You can use the filter function to prevent duplicate entries in an event registration database and to match records when people are canceling. Through the submit_time field you can search for an entire record and delete it with some basic MySQL.

Minor downer: due to the blog style layout the documentation is somewhat unorganized.