I've used Big Bud in the past it worked wonders but it's not a stand alone nutrient for producing big flower. You'll need B-52, bud factor and sensei bloom.
@Fruitgrower Hi mate they are all basically the same thing with the same ingrediants just with different hype
and marketing techniques.
I would personally go for any of the brands that do not have any of the bad pgr's in them or organic is even better like guano. https://www.marijuanabreak.com/plant-growth-regulators-in-weed