Pete gives as good an answer as possible…
But I can give you two exact comparisons of MLF (7 foot Legend Elite) and MLXF (6’9″ Legend Extreme)for pitching jigs.
I can toss jigs about the same distance with both rods and the sensitivity was about the same (although the Extreme is a bee-u-ti-ful rod to work!).
The biggies for me and why I went to 69MLXF is the amount of rod that flexes. I didn’t really like that the MLF rod had more bend along the whole blank. MLXF has less bend along the whole blank and is easier to work jigs and set the hook.
All this is just my own use with both rods and not really the “rod” language. Hope it helps you. I’m sure that there are others that love MLF too…best to try some out.