Before going into what is good about iBattz, I want to say what tick me off when I was using it. Initially I dislike the extension speaker as my headphone jack is unable to plug in directly. With the given cable extension provided, I find that the cable is too long to my liking. After studying the iBattz Mojo Refuel, I learn that this might be the best position. Apple has change the audio jack from top (beside on/off button) to the bottom, which makes life easier for us to cover up the exposed area (speaker, charging port and audio jack) with one hand. I realise this when I am trying to protect my water from sipping into my iPhone when it started raining while I was walking in the streets.
Full article: http://justinng.sg/2014/02/28/ibattz-mojo-refuel-review/