At the Capitol Audio Fest 2 years ago, I heard the SoundScape 10 and what I believe is the Wilson Sasha. The Wilson web site shows the Sasha W/P and the Sophia 3, and what I saw that day had 2 woofers (each roughly 7") in the lower cabinet like the Sasha.
Both rooms in that hotel were the same large size, roughly 25'×25', and the Salk and Wilson rooms were right next to each other, allowing for nearly direct comparisons. In my opinion, it wasn't close. I thought the SS 10 was without question the best speaker I've heard, and the Wilson was so very bright sounding that I had to leave the room before long. The bass seemed good, but the upper ranges were voiced too hot. In the short time I listened to it, I couldn't make any other observations or impression because of it's unpleasant – almost painful – bright sound.
The SS8 is a somewhat less expensive version of the SS10, but they share midrange, tweeter, designers, and the resulting voicing. I don't know if the Sasha is similar to the Sophia.