I've listened to both side by side in the same ($20K tube) system. As indicated, the K-horns were designed specifically to give optimum performance placed in the corners of the room. They are also quite larger in height and overall volume than the LaScala's. The sound of both is quite clean and forward, but the Khorns give a more authorative and lower bass (placed in the corners) than the LaScala's. I could certainly live with either given the right space to put the K-horns. The LaScala's may be more versatile since they don't have such rigid placement requirements. I own 1977 LaScala's and absolutley love them. Never heard a pair of ESS/Heil speakers so cannot comment there. I would not use either Klipsch with a SS system, but there are those who would disagree on that point. My opinion is that it that there are better combinations than SS + horns. Tubes + horns is heaven to my ears when done right.
Marco
Marco