Recently,
First Endurance was called to stack up its own EFS electrolyte hydration mix against the low calorie offerings from Skratch Labs and Osmo. What came from it was very interesting: by cutting the serving in half, you can get more electrolyes from EFS, with less sugar and more amino acids than either Skratch or Osmo.
Check out the data below. Pretty impressive!
http://firstendurance.com/2014/08/11/efs-vs-skratch-labs-vs-osmo-an-electrolyte-hydration-drink-comparison/