Since forever.
Here's my set:
Greninja @ Life Orb
Ability: Protean
EVs: 252 SpA, 252 Speed, 4 HP
Timid
-Surf
-Ice Beam
-Grass Knot
-Dark Pulse
With timid he outspeeds 99% of things, and even Noivern only beats him by 2 points. [That's why if you run Noivern you should reduce his speed by 1 to give him an extra hit point]. The point of this set is coverage and damage. You can get SE on a lot of things, Grass Knot OHKOs other Greninjas and does huge damage to things like Snorlax and Tyranitar [even with assault vest on]. Surf is taken over Scald for a bit more punch.