I'm just curious which method you use to check the input is there, not how to validate or sanitize, but if you think 1 is better or why you use

Code PHP:
if(!isset($_POST['txtField1'])
{
echo "Sorry that is a required field";
}

vs

Code PHP:
if(empty($_POST['txtField1'])
{
echo "Sorry that is a required field";
}

it's just all about my making my code and clean and solid as possible.

Thanks