The Toxin and the Shock share the same spot in the line-up, but at different times in Motiv's history. Motiv had great cores early on but their covers could not compete with the Storms/EBI/Brunswick covers at the time. Consequently, the complete lineup was a little weaker overall when compared to other companies complete lineup.
The Toxin is a great ball with a shape similar to the Venom Shock, but the Venom Shock cover is stronger and the ball in general is more predictable with the Turmoil MFS coverstock. This is especially apparent on flatter shots.
In the current Motiv lineup, the Toxin would fit in a space between the Shock and the original Ascent in strength. In fact, I feel Motiv needs a ball similar to the solid Ascent it used to have. But that is a different story.