I don't remember the exact gain increase, but unless you max it, it's nowhere near as big as the gain from "Lucky Egg" and "Exp O-Power level 3". So I'd recommend finding a Lucky Egg and using the O-Power instead.
I don't remember the exact gain increase, but unless you max it, it's nowhere near as big as the gain from "Lucky Egg" and "Exp O-Power level 3". So I'd recommend finding a Lucky Egg and using the O-Power instead.