FYI he DM'ed me a link to his sub that is better and cheaper than my Sonos sub.
Spoiler - it wasn't cheaper.
To be fair, he didn't say it was cheaper, he said it was his cheapest.
There's a lot of hyperbole being thrown around both ways here.
Sonos will be simpler to setup, but a properly setup eARC receiver is very easy to use. I don't have to touch my receiver when using my TV / blu ray player, it all just works. I could.use voice control as well if I wanted.
I've not had Sonos myself but family members really like theres, and the sound quality is decent imo.
That said, for a dedicated room, you can get a better experience for the same or less money with separates.
There's some bargains to be had with second hand speakers which don't change all that much year to year.
I also wouldn't count out Atmos for a dedicated room (even if you don't install to begin with). I've got a 5.1.4 setup and the Atmos adds an extra dimension in well mastered films.
Definitely worth trying to get a few demos if you are not convinced though.