Well, I has able to audition some SongTowers today. Thanks go out to a most generous member here, et+kooper (thanks Bruce), for letting me interrupt his weekend. Bruce showed me his impressive HT setup, with STs for the L/R mains. I brought along my Studio-20s in order to compare them, in the same room and with the same electronics.
We first listened to the STs, in 2-ch mode. Very impressive, with a lot of body to the sound. Then we tried my Studios.
The Studios , to me, definitely sounded a bit too "trebley". The treble seemed overly accentuated, fatiguing to listen to, IMO.
It's funny, I had liked my Studios at home but, had gradually recognized that the treble (high frequencies) bothered me. It wasn't until I could A/B compare against the SongTowers that it jumped out at me. Additionally, I felt the midrange of the STs was excellent, with good detailing.
In addition to the STs, I was able to listen to Bruce's very nice disc player, a Oppo something or other ... maybe 95??
I currently use an Emo ERC-1, which is nice but, the Oppo was excellent and can handle SACD, DVDs, and other formats.
To summarize, I now am looking at a Salk upgrade and also an upgrade to my CDP.