I guess everyone carries at least one portable charger (power bank) with them whenever they go out. It has become an essential as our phones are now taking over our lives.

I'm a gamer, so a power bank is a must-have when I leave the house. We've about 8 power banks at home (all different brands and sizes) that we share among ourselves and the Xiaomi NDY-02-AD is not exactly one of my favourite.

It works as it should - charging itself and then charging my phone. Its design is pretty good. It doesn't looks cheap, in fact it feels a little modern and the colour is pretty attractive. It is very solid. Its outer cover, unlike most power banks is made of Aluminum instead of plastic. It could be its solid cover that makes it rather durable, dropped it more than a few times and it's still going (I've had power bank that died after 1-2 drops). However, this is also the problem with it. It's heavy, heavier than most other power banks I've ever used. To be honest, I don't exactly need to bring a paperweight if I can bring something lighter out.

I don't really keep track of the charging time of the power bank neither do I keep track of the number of times it can fully charge my phone. A rough gauge would be around 7-8 hours to fully charge the power bank and it can fully charge my iPhone 6 Plus for about 4 times, depending on usage.

I like the LED feedback from the power bank while charging. There are lights to indicate how much battery is left and they blink when charging. It's very important for me to know how much juice I've left and if the charger is fully charged at all. I've had power bank without such feedback and I don't like the unpredictability.
I've been using this power bank on and off for about a few years now, I don't find any major problems with it however, it does have some small little ones. It's not very reliable. The power bank can just randomly stop charging my phone. It can be easily solve by removing and re-plugging the cable. Fortunately it doesn't happen often in fact you can say it rarely did. I still don't know why and what caused it to happen - Because it happens both at home when it's place on the table overnight and when it's in my bag. (But it could be because I've dropped it before.)

I am not sure if I want to recommend this product, as there are plenty of power banks that are lighter and more stable than the Xiaomi NDY-02-AD out there. However, this power bank is relatively cheaper. If you're on a budget and you don't mind the weight and occasional hiccups then it's a pretty good power bank.