Bests & Worsts Reviews from Amazon

I purchased this when I first bought my S4 due to good results with my iPhone. I will separate this into pros and cons. There are several large flaws in this product that is not stated on the box! This was a new unit being used with a factory battery on a new phone. These observations are after 2 weeks of use. There are several important cons so please read my recommendations before purchasing. Pro's -Adds to the time you can go between charges -Has a nice rubberized feel -Doubles as a case -Ability to turn charging on and off Cons -Blocks the use of NFC not stated on packaging -Blocks the use of S Beam also not on packaging -Consistently lost 2-5 db of signal strength despite their claims of no signal loss. This made the difference between dropping calls and having data coverage where signal was weak and having to remove it to make the call. -With the Juicebox installed the phone will not go into dock mode due to the lack of pins that the Samsung micro usb cable use on their docks -Without the Juicebox installed the charge rate with stock charger and usb cable is 1200maH with it installed and fully charged it only passed though 740mAh with it on or off! -You theoretically add 2200mAh but loose around 10+% due to the inefficiency of charging circuitry plus they also only recommend turning it on when the factory charge gets down to 20%. I don't want to have to watch my level all day. All that bulk only gets you 1980mAh battery at absolute best! -You cannot use headphones with a 90 end due to the case being too thick, they will not reach the connector -Adds considerable thickness and height to the phone In summary this feels and acts like a product made to work around any phone with a micro usb connector than one specifically for the Galaxy S4. A much better work around I have been using is the Hyperion 5200mAh battery and Seidio case for their extended battery. The charge rate is 1700mAh and the phone lasts for 3 days with average use! There is no blocking of the factory antennas for Samsungs NFC, S Beam or phone signal. My dropped calls and signal strength went back to stock, the headphones fit, dock mode works, the phone lost almost 1/2" in height due to the juice box design, A full charge takes only 2-3 hours vs overnight. I have yet to find a negative with this combination except I wish I saved the money and did it first. I hope you find this informative and save your money, I wish I did.