I know this is only my experience but I will share my impressions. I don't have atmos yet but in my last house my living room/theater was 12ft wide and backed on to the dining room so I had the back speakers hanging from the ceiling for 7.1. I had many iterations of speakers in that house and for me front heights did way more for the enjoyment factor than the rear surrounds ever did. I now have a new house with a basement room that is 15x15 so I went 5.2 with QS8's which are about4 inches from the hanging ceiling and couldn't be happier. Room treatments are the biggest improvement you will make by far, rather than more speakers imho. I have not heard atmos but I always want the latest and greatest but I am really waffling since what I have now works so well. I really think 5.4 will be more than enough, really 5.2.2 should be more than adequate in a room that size.
Richard
