//create record
   $rec = $fm->createRecord('layout_name', '$data_array');
   $result = $rec->commit();

   //new add command
   $newAdd = $fm->newAddCommand('layout_name', $data_array);
   $result = $newAdd->execute();


//Second and main difference is what they return to $result variable. The 'createRecord()' statement returns an integer value to know the status of record creation process(whether succeed or failed). But the 'newAddCommand()' returns a bunch of information for the new created record along with record id.