I have a Zagg InvisibleShield fitted. Took me ages. The back is on fine, but the front really f*cked with my head! Its still not 'perfect' and I can't do it again as I have run out of the 'solution' and its stuck on quiet tight. My front shield is particularly 'orange peely' and its ruining the 'retina display' experience!
Careful when applying the shields, its a wet application so keep it OUT of your speakers/holes etc when applying it! Also, do NOT get ANY dust / dirt on the shield, its impossible to get it off! I soaked my front one in soapy water, let it dry a bit and it got just as sticky again, then applied it with the solution again.
Fantastic if you can get it right, covers the front back sides etc. I didnt bother with the sides as I have a 'bumper'. BUT, putting the bumper on makes the shield peel a bit, and youre supposed to let it 'cure' for 12+ hours. Mines been on 2 days and its still f*cking peeling.
Gonna order a replacement and try again methinks!