Just got it and put it on about an hour ago....so far this is my favorite case yet. The surface case that you can use without the protective outer skin feels slightly cheap compared to the mophie but once you put on the protective skin and skeleton thing, it feels REALLY solid and like it could totally handle a drop as good or better than an otterbox or ballistic.
It adds some bulk, but honestly not much more than an otterbox defender and this has the battery built in where the defender obviously does not. It also adds some weight but I'd compare it to the mophie that I had...pretty close to that. My uncle has the same case, and he said his phone died this morning so he turned the case on and it charged the phone to 87%, so I will be completely satisfied with that if that's the norm. I don't NEED a battery case, but it'll be nice to have just in case.
So basically i'd say this has the best of all of the protective cases PLUS a battery case rolled into one...plenty of drop protection, feels really solid, helps battery life, better dust protection than otterbox, and no built in screen protector (I see that as a plus, never liked the built in kind)
Going to return the lifeproof that I was using this evening if that tells ya anything. Lol
Any other questions feel free to ask!