Hi Ross,
Thank you, you showed me the light 😉
Here is my approach (I am using the Advanced Custom Fields plugin for meta values):

<?php 
          $copy = array();
          $is_search = false;
  	  $search_query = $wp_query->query;

          // META
          if($search_query['_sfm_location']){
            $field = get_field_object('location', false, array('load_value' => false));
            foreach ($field['choices'] as $key => $value) {
              if($key == $search_query['_sfm_location']){
                $copy[] = $value;
              }
            }
            $is_search = true;
          } 

          // TAXONOMY
          if($search_query['_sft_project_category']){
            $term = get_term_by('slug', $search_query['_sft_project_category'], 'project_category');
            $copy[] = $term->name;
            $is_search = true;
          }
  ?>

<?php if($is_search): ?>
  <p>Searching filters for: <?php echo implode(', ', $copy); ?></p>
<?php else: ?>
  <p>A simple copy when if no search.</p>
<?php endif; ?>

Yes!
get_fields() and get_field_object() does grab all custom fields info
http://www.advancedcustomfields.com/resources/get_fields/

Hi Ross,

I am back on this topic.
I created a dropdown field with your form, then filled it with some options.

Now i want to retrieve those options to match them to $wp_query->query and display the proper heading statement.

Thanks!

Sorry, i was too straightforward. I put it another way:

Imagine I create a new form. Create a new field, type Post Meta. Then i choose to Display my Meta Field with a dropdown, which I manually fill it some options: value_1, label_1, .... value_n, label_n. Done.

Whan I submit the form and go to a new page, i will e able to retrieve the value_n via wp_query, but then how can I get the corresponding label_n

Thank you!