Originally Posted by The Uprising
It gives stacking movement speed if you're attacking... unlike her current ulti, it breaks stealth upon activation.
That's a moot point if you only use the Active when you get in vision range. The times you would want to use it to engage, you're already in vision range anyway, so you don't lose anything for breaking stealth. Meanwhile, you can also use it to increase the distance as an escape (but not during the escape, after you stealthed; that seems like an intended balance tweak).
You're rewarded for using it aggressively and you only have an 8 second window to use it as an escape