Isset and IsNotEmpty operators have for sure been a hot topic for several years now and in my opinion rightly so. The non-DRY style of:
$my_array['my_long_boring_key'] = !empty($my_array['my_long_boring_key'])
? $my_array['my_long_boring_key'] : 'Default value';
$my_array['my_long_boring_key'] = isset($my_array['my_long_boring_key'])
? $my_array['my_long_boring_key'] : 'Default value';