Main difference between 20 mule team and the borates sold as miracle pool additives is the price and the number of water molecules attached to the borax molucule. This just means that on a weight for weight basis one will supply SLIGHLY less borate. Their action once dissoved is indentical if the ppm borate is the same. Considering the HUGE difference in price I will stick to borax! Some of the pool additives use a mixture of sodium and potassium tetraborate but this really has no impact on it's effects. Probably more a price thing for the manufacturer.

(Yes, I admit that I like to read MSDS for fun. You can learn a lot that way!)