Also depends on where you live, if you're in an apartment, neighbors might thank you for not having a sub with your Arc. I have Arc+sub+surrounds, I normally keep my sub turned down a bit.
I've said the following many times here
- the direct audio connection on sonos, vs streaming over the network is much less prone to failure or delay. Some apps are worse than others when dealing with airplay.
- on sonos, you can control music from ANY device on your network. Chose music on an android, skip a song on iOS, chance volume from your Mac, and stop playback from Windows. and that's all for the same playback "session"
with HomePod there is some control on the Mac using the music app, but currently only if you're playing Apple Music. (other services suppoesedly coming soon)
- Sonos can access many more streaming services, you can even make a mixed playlist with songs from multiple services.
I've tried channel check files with the arc, with each channel isolated including the atmos, and the height channels definitely sounds "higher" than the regular left and right channels.
I can try with my HomePod and see how it goes, although I'll have to play around to make sure it's actually playing the atmos test file directly and not converting. I usually use an app on the TV to play it.