I bought this because I wanted to run an experiment and power a Zoom B6 with it and free myself of some unwanted cables. The first few tests were promising. I tried it first during a few 4-h bank rehearsals. Packing up I checked the power level: I had over 50% left! My firs thought was 'Is this really only 10k mAH? Amazing.' The B6 doesn't require an extreme amount of power, but this was beyond expectations.
First time I took it to a show with me I was still a bit sceptic and brought a backup power supply and extension chord with me. Better safe than sorry, right? I didn't need to worry. Still 50% left after the night was over. I'm leaving my power supply at home now.
The B6 is the only 'pedal' I've powered with it, so I have no experience with having 2 pedals attached at the same time. However, charging my phone at the same time appears to be fine. I know I have enough power on tap to charge it long enough to get back home and still have enough to power the B6 during my rehearsals. Not a peep from my B6 while charging my phone either. No noise, no disturbance, no hickups, nothing. I'm considering getting a 2nd one as a spare.