I'm not a receiver person -- to me a receiver is a radio -- but way back around 1978 I was shopping for a receiver for a matron of my acquaintance. The shop had a cheap 15-watter on closeout and a more deluxe 20-watter for a chunk more. The salesman was trying to move me into the more expensive one, but the smaller one obviously sounded better. More dynamic playing the jazz records that she liked, clearer, cleaner, not harsh like the other.
Who knows why. Since then a whole art of audiophile design has evolved, and as with every intangible pursuit, it attracts plenty of charlatans.
But this was true then and its true now: If you're looking at watts, you're looking at one thing and sound quality is another thing.