Got to concur with a good few of the posts here about room size. In a small to medium room the S20s are very musical and enjoyable - their downward dispersed port is great for these rooms. Heard in rooms up to approx 15ft by 13ft they work really well. A rare thing, a serious floorstander that works well in a smaller room.
However, in my 12ft by 19ft room (firing down the length) they sounded a bit lost and consequently rather bright. So best checked in the room they're going to go into.
BTW, on the 'too hifi' definition, I agree its a bit lazy and I'm probably guilty of using this phrase. For me it refers to a component or system that seems to major on an apparently technically empahasised presentation (eg. too much treble to seem detailed, a pushed forward vocal range to grab attention, over inflated bass to appear to go deeper than it actually does, as a few examples) but forgets about flow, timing, expression and other aspects of a musical performance. In other words, no emotional connection to the music or artist.