I heard the SP1 at AXPONA this year. The overall sound was impressive, with seemingly low distortion and wide coverage area, though I found them a bit bass-shy. (I'm reluctant to attribute that to the speakers, rather than the room/setup, though it can't help having the bass reproducer that far off the floor.) I also found the SP1 visually large and imposing (as @EkW said) and not attractive visually to my taste.
If a person is looking for an electrostatic speaker, if a very wide sweet spot is important, the SP1 would be a great choice. If a narrower sweet spot is acceptable and less obtrusive appearance is also needed, the Janszen Valentina would be my pick (I own a pair), with comparable sound at about half the price. The Janszens *might* have better bass, too.