I never go for the one number quickie list. Don't care if it's OPS or WAR or any other single number, traditional or advanced. It is always an over simplification. Each hitter is unique and brings something different to the plate. I like to see if they are maximizing their particular skill set. For example, with JBJ and Moreland I focus on their extra base hitting. With Mookie and JD, I expect strong numbers in all categories.
With OPS, you are adding fractions with different denominators, PA's and AB's And all you are doing is adding together two traditional statistical calculations. On top of that, SLG is only a crude calculation of power hitting. So OPS is in no way an advanced or better metric than the very traditional numbers is is derived from.