I have one right now. It is the meanest of the fish I keep with it. It routinely gives the other fish grief when they get into his area. The other fish include a Picasso Trigger, Coral Beauty, Majestic Angel, and a much larger Clown Trigger (He doesn't mess with the Clown Trigger often). He doesn't try to hurt them just chases them around a bit.
I made the mistake of trying to add a Naso Tang a few weeks ago. The Sohal went after the Naso with a passion. After 30 minutes I had to remove the Naso as it was beaten up badly. The Naso is doing much better now in another tank.
The Sohal Tang is a great fish, but they also grow pretty fast.