Flurry
You smack an opponent repeatedly with a punching combo. Does a decent amount of damage and has a chance to disorient, but has a fairly long activation time (about 3 seconds) during which you won't be able to launch other powers.
It's a pretty strong attack (especially for low damage players), but almost everyone takes Hasten for the faster recharge to ALL powers. Still, I've always wanted to make a Dark Melee scrapper who took Dark Maul, Flurry, and Sands of Mu (all powers with the exact same animation), but I'd actually have to play long enough to get the Sands of Mu veteran reward…. (Edit: Woohoo! I made it and it's an AWESOME concept… Tons of fun to play!)
In the end your main reason to take this power is for a concept (like I did), or because you're playing a weaker player that needs a strong melee attack.
In this pic, I show Gale running with super speed and leaping off a tall freeway. She's wearing her new outfit (that I still haven't managed to get in the comic yet) and I used this as Gale's Storm/Sonic guide.
You can see the pencil sketch here.