I have like 2 minutes is all, so just going to fire off some comments...
The 720 is a 7.x receiver, where the 1120 is a 11.x receiver.
720 can do 7.x or 5.x.2 Atmos (can go to 7.x.4 with 4 more channels of amplification)
1120 can do 11.x or 7.x.4 Atmos (all with internal amps)
Anthem receivers have ARC (Anthem Room Correction) and it is supposed to be really, really good.
The 1120 has a Toroidal power supply that is supposed to improve dynamic range (can hit louds quick, and drop power super fast for changes in output levels).
Anyway, that is what I could come up with in 2 minutes.
