I made a big thread about this long ago so don't feel like redoing it. However:
Looking at the feats of both users AND the times at which they were used.
Itachi Amaterasu:
High Intensity, Burns faster, and spreads rapidly
Sasuke Amaterasu:
Lower Intensity, Burns slower, and controllable
Analyze there feats and you will see
Itachi Amaterasu feats:
Burned Toad Stomach
Charred Chimera
Charred Nagato
Charred Sasuke's Clone
Sasuke Amaterasu feats:
Slow burned Danzo
Slow Burned Karin
Slow Burned Bee/Gyuki
Didn't burn Samurai armor
Didn't burn Madara
Anyways, I will probably find that old thread of mine but just wanted people to stop mixing feats
Looking at the feats of both users AND the times at which they were used.
Itachi Amaterasu:
High Intensity, Burns faster, and spreads rapidly
Sasuke Amaterasu:
Lower Intensity, Burns slower, and controllable
Analyze there feats and you will see
Itachi Amaterasu feats:
Burned Toad Stomach
Charred Chimera
Charred Nagato
Charred Sasuke's Clone
Sasuke Amaterasu feats:
Slow burned Danzo
Slow Burned Karin
Slow Burned Bee/Gyuki
Didn't burn Samurai armor
Didn't burn Madara
Anyways, I will probably find that old thread of mine but just wanted people to stop mixing feats