Berkley, Propure, and Alexapure are the best brands for at home water filtration. They remove heavy metals, fluroide, chlorine, pharmaceuticals, pesticides, ect. Per gallon, they are less expensive than any store bought brand.

However, Brita is decent (doesn't filter pharmaceuticals) while still being a very consistent product.

I haven't looked into reverse osmosis, but have heard good things about reverse osmosis spring water, which has a high electrolyte content.