Engagement. If the system, modest or mammoth, engages you then it's all good. If for whatever reason it doesn't engage you, you'll never be happy. The Large Advent was far from perfect, but with a good 30-60 w/ch amp, and a decent turntable, they were engaging with almost any type of music. An NAD 7120 20 w/ch receiver and a pair of Magnepan MMGs (in a perfect room for Magnepans) was transcendent, if not loud. The Sonos Ones Streaming Amazon }prime UHD are stunningly engaging in a smaller room, especially after being tuned with their TruePlay DSP - and they're under $400 a pair. One the other End, a pair of Wilson Sasha DAW fed by about $40K of Jadis tubes and a VPI HRX/Koetsu front end made mincemeat out of a $100K budget - and my ears, in the best way possible. These systems couldn't be more different, and that's my point. The one thing they shared was engagement. They made you want to listen to another song, another album. They engaged you.
