I prefer the OG EJ07 over M9 for my library which is mostly metal. Ofcourse the fit is better for my ears and love how the EJ07 brings out the guitar in the mix. Bass timbre is better obviously because it’s a DD, snare tone on certain tracks feel very accurate. Treble is very smooth just like M9, maybe a lil less in comparison unless you crank the volume. Some might find it lacking here maybe? I happen to enjoy this tonality over bright sets. Soundstage and Imaging is better on EJ with more 3D like. EJ07 sound better with some extra power which is not the case with M9. All said both are great sets, for an all BA set M9 is quiet the wonder.