The Anthem will be more detailed and neutral sounding while the Marantz will Sound warmer and fuller with with a more polite and less detailed treble range. Choose based on which best suits your system and tastes.
FWIW, I was very impressed by the Yamaha Aventage series compared directly to Marantz, Denon, and Arcam, and importantly Yamaha has proven to be more reliable than most other AVRs out there. Like the Anthem it is more in the neutral camp, but the level of transparency and its better 3D soundstage won me over big time and would likely be a good bit cheaper than the Anthem. Just another potential option. Best of luck.
FWIW, I was very impressed by the Yamaha Aventage series compared directly to Marantz, Denon, and Arcam, and importantly Yamaha has proven to be more reliable than most other AVRs out there. Like the Anthem it is more in the neutral camp, but the level of transparency and its better 3D soundstage won me over big time and would likely be a good bit cheaper than the Anthem. Just another potential option. Best of luck.