I fooled around with MacIntosh and ARC, once upon a time. It was expensive. I ended up dumping all my Macintosh for all brand new ARC equipment. Nowadays I have a mixture of ARC and solid state.
I think the comments above are correct, Macintosh is not so defined and more boomy. The ARCs tend to have finer detail and a more open presentation.
Saying this I know Macintosh enthusiasts will defend their product to the end and so be it. But I have to treat it like it’s just another piece of audio gear bought and sold.
In the end both companies are fantastic and you pick or you choose the one you wish.
Certainly you are not hurting with either.