With MySQL we have a few easy choices for working with the DBMS (PDO, MySQL, MySQLi). I am going to be working with MSSQL on a project which isn't a problem but as with MySQL they're a few choices when it comes to working with it: MSSQL Extension and PDO being the most obvious.
Is there a better route to go down? The application will only ever be on a IIS, PHP, MSSQL environment so deploying it on other environments won't be something I will need to consider.