i bought a "full body kit" from Zagg and i can say i am not happy with it.
the touch and feel of it is rubbery and "squeeky" im not sure how to put it, lets say when you slide your finger over the display (or any other part of the phone if you get full body kit) there is a lot of friction and its not as smooth as without it, i could make it do squekky sounds when scrolling a webpage for example.
there was no piece included to cover the camera!
i put the phone in the case you get with the phone and i almost didnt get it out, you might imagine the diffrence this does to the surface of the phone.
also at all the ends of the diffrent parts of the invisible shield (for the 5800xm full body it comes in 8 pieces) its very likely you will get dust and such and it doesnt look good..
i also noticed that the display lost a bit of sharpness when using it, especially when there is a white background. i think this is why they dont include a piece to cover the camera.
But the good thing is, its VERY resistent to scratches.
i dont recommend it cause it changes the look and feel way too much for my taste, i have taken it off.