You can tailor your training to fit your needs.
It all revolves around perceived intensity. No and low intensity for programmed recovery.
Moderate and high intensity to kick it up. So, if metcons are "harder" for you than ME work, then it should be on the high day. If it's the other way around then that's the way it should go.
Generally though it is recommended (for most) to do your strength training on your moderate day and metcon on the high day, as (again generally) the demands on the body from a metcon are higher then most strength days (if you're doing it right