Buttons on the device are hard to press and unreliable. Terrible documentation that reads more like a sales pitch than actual help. Wake up requires a pogo pin that basically marries the hat to the particular model of Pi you can use with it, and it's not very well marked on the board where (and how) to set it.

Command line interface is just a text based GUI instead of just letting you dispatch shutdown/power off commands, or read battery charge remaining. This severely limits the utility of the device unless you want to break out a Python script (The calls are supposed to be already done to support the GUI, so why do users have to reinvent the wheel?). It doesn't log keypresses or power events.

It looks open source, but look closely. From the Github: "The firmware source code is not intended to be made openly available as it requires deep understanding of the hardware design and the programming involved if you wanted to customise it."

My project needs some flexible power management and a COTS hat to make this happen sounded very attractive considering the work involved, but I basically wasted my money and will have to build something more useful instead.

But, hey, it's got an RGB LED on it. :/

It took me a while to test it and make sure I could use it in my application, but I am completely satisfied with the PiJuice. I would recommend it without restriction.

I bought this hoping that I sould use it with a Zero V 1.3 (not a W!) to do some presentations (demonstrating that a $5 computer is a serious computer). First minor problem is that I had to remove (unscrew) on of the standoffs to get access to the Zero's HDMI connector -- not a biggie, but could have been mentioned in the documentation.

More significant is that it goes from 97% capacity (never does reach 100% capacity) to down in the 40's in about half an hour, so I can't use it to provide all the power for a roughly 1 hour presentation. (I have a Ethernet/USB Hub, and a "generic" USB mouse and keyboard, attached as well.) Not sure if buying a new BP7X locally would improve it enough to be worthwhile.

Even more significant is that, in my humble opinion, it's FAR too easy to accidentally hit the "ON" button. I might be able to rig some sort of protector for the button, but this is a serious problem. Taking out the battery pack would cause the RTC to lose the time & date, which would also be a problem.

It's also annoying to have LEDs flash at all when the unit is turned off and not attached to an external power supply. (I can just picture the raised eyebrows of a TSA agent...) I'll have to remember to turn off the LEDs (in software) before air travel, then use the aforementioned Ethernet connection to log into it at the other end and re-enable the charge indicators. (I'd suggest a "firmware" enhancement - if the Pi is turned off, and no external power is connected, turn OFF the LEDs, but if one of the other buttons is pressed, show an indication of charge for 1 second.)

This unit has some interesting and useful features, but does have a few problems as well.

It best product.

Easy to set up, provided power well, but not long. Battery dies in less than an hour, but there are good tutorials on how to add a bigger battery. But the worst problem by far is that for some reason it blocks the WIFI. I can connect about 10% of the time, then the wifi just cuts out. WIFI works fine on the Pi without it... consistently not with it.