Effect Spore: You Cannot attack the opponet and inflict a status, they have to hit you with a physical attack. Burn Not Only Does Damage, But Lowers the burned pokemons attack, therefore, I give Effect Spore 2 Point Because burn is so helpful. Sleep gives you a HUGE Advantage, the opponet being unable to attack, I award another point to effect spore. Poison is Incredibly Helpful, lowering the opponets hp well. Therfore, Effect Spore Finishes with 4 Points.
Poison Heal: Toxic being such a Popular move, this can be incredibly helpful. For This I Give Poison heal, 2 points. There Are Lots Of Poisoning moves, and as most Brelooms have Effect Spore, This Would Be Unexpected, therefore I add 2 points to Poison Heal.
OVerall: Poison Heal and Effect Spore are Both Great Abilities, so from the reasons I gave you, choose the one you like(though presonally I like Effect Spore better):)
Hope This Helped:)