i have both fish in a 100 G grow out tank. their around 4'' , the Jag is really Aggressive it will constantly chase fish around the tank while the Devil/midas will just bite no flaring our anything. they got in to a semi fight yesterday but i broke it up because i hate seeing my fish with torn fins

The Jag looks like it won because the Devil now runs from it :/ in my opinion the Devil is more Aggressive but the Jag will win a fight one on one . 18'' male Jag vs 14'' male devil ... the jag has size and a larger mouth . this video on youtube shows you what the fight would look light between a full grown Jag and a full grow midas even though the midas in this video was defending fry it still couldn't win
http://www.youtube.com/watch?v=p4Oz9rVxgLw&feature=related . look at the bite marks on the poor fishes face

this is animal cruelty but its answers your question