Alright I'm not trying to suppress your answer or anything, but I will go into detail.
With Pokerus, horde training definitely
With Pokerus, this thing is pretty darn fast. Paired up with power Items, it will literally only take what, 10 minutes max?
Without Pokerus, Super Training
Alright. In Horde Training, without Pokerus, they give off a maximum of 14 EVs for all final evo hordes such as Drapion and many more. Super Training gives you 12, not much of a difference.
Training an entire party
Definitely horde training. Super training takes 20 minutes per Pokemon at least. Horde training may take 30-40 minutes to complete the entire team, but better than close to an hour.
So the final verdict:
No Pokerus: Super Training
Yes Pokerus: Horde Training with power items
For an entire team of Pokemon: Horde training as Super training might take a while.