For my part, I put 5 stars to this external battery for it constantly serves me for my phone! I charge once for about 5-6 truck loads - that was one of the key buying criteria: that the battery can charge more than 2 times the phone before recharging itself from the mains. The durability of the battery will see over time but given its composition and if taken care, it will last !!! For cons, the negatives would be taken to provide a usb-> sector which is not supplied with, the fact also have the cable usb-> phone to phone and charge said battery weight is still " heavy ", but it goes in a bag. Expect also to what you chippe your battery to charge the phones of each other, since its capacity;) Anyway around me, it was unanimous!