I enjoyed my Arcs campaign playthrough, but it'll be a long time before I put it on the table again. By the third act, the energy was very low (even though we played over 3 days).
I've played the campaign a few times now (10+) and my advice is
1. it's much better/ more manageable at 3 players unless everyone is already pretty experienced.
2. Try to play the first two acts in quick succession then the third maybe a week later once the dust has settled.