All season long I've felt like Amir's pick and roll defense is at least substantially better than Horford's. Especially when there's only 1 big out there and Amir gets to be the 5.
Granted, Horford's rebounding, passing, and post defense are better, but that smallball lineup with Amir is dangerous and arguably our best defensive lineup overall due to the pick and roll coverage, and their ability to switch and scramble/recover quickly on rotations.