The battery allows me to charge 4-5 times my iphone 5S completely (about 10% to 100%).
I had some concerns about the consumption of the LED facade (which light up when the battery is shaken), but in the end I have not seen real losses by leaving it in a backpack.
I tested the simultaneous charging of a 5S + a galaxy s4: no problem, and everything rather quickly (about 1:30), without draining any battery (less than half of the consumed load).
Short but good! Fully charging the battery takes about ten hours with an iPad charger (12W model).
It remains to see the behavior in time ... But for now, this is a product that I am fully satisfied and I recommend :)