Hi Chris,
I have done the exact journey you are about to start and am now on the other side 😀.
My progression was Marantz to Arcam to Anthem and then back to Arcam.
What got me back to Arcam was its richer, more lush, and midrange denser sound. More bloom and presence for voice and instruments. More airy dense sound field when in surround.
The Anthem was also good in details and surround but I found it have a cooler and less rich sound. Not bad by any means and I don't mean this as a negative. If one prefers a clean impactful sound then this would be the preferred avr.
For my tastes the richer sound field of the Arcam won out.