Alakazam
Pros: High S.attack and Speed with a great movepool and a great new ability that helps alot with life orb sets.
Cons: Super fragile and dies from almost any physical attack and less than desirable offensive typing
Chandelure
Pros: insane S.attack and decent bulk, speed with great unique typing,great abilities, and amazing movepool
Cons: a let down speed of 80 that requires baton pass, trick-room+iron ball, or choice scarf
So if a fragile sweeper is what you want Alakazam is majorly awesome. If you have access to baton pass speed boosts Chandulure pwns.