I just finished a couple of long sessions with a pair of these. During the first session, which was mostly flow-posing, we banged out 1860+ shots in just under 4 hours including 7 wardrobe changes. Out of those I experienced just 6 non-fires - mostly when I was impatient to wait for a recharge. Shooting manual mode at 1/16th and 1/64th power, the key light battery showed 50% at the end. See attached contact sheet.
During the second session, approx 800 shots (this time in TTL mode) no non-fires and and maybe used 30% battery. Brightness and color consistency were both excellent during these shoots. You can see my unboxing and initial product review on https://youtu.be/rFKJ-XscCpA