I only had the device for several days now but so far I am extremely happy with the IMP52D.  I received the IMP52D the day before I left for vacation so I had a chance to use it extensively for several days now.  I purchased the unit for it's generous 5200mAh capacity, competative price, attractive looks, and most of all from the experience I had with other NewTrent products I own.  I am a little bit of a mobile electronics junkie.  Never traveling withour my iPhone, iPad, laptop, and camera.  I also use electronic cigarettes which charge via usb chargers.  A backup battery or several backup batteries is a must.  I have tried several of them.  Because I wanted the flexability of charging several devices from different manafacturers I did not consider iphone or ipad cases that snap on and extend the battery of that specific device.