Got a Nilking case today. I had the same one when I had Moto Razr and decided to try it on my S4. It fits perfectly, and just as with the Razr one I had to cut off the pieces that sit next to power and volume buttons to make them more accessible. It is not a case that protects the phone from any crazy stuff, but I do not plan on throwing it at people or anything like that, so it should be sufficient.
I also got a replacement battery cover which imitates leather and it is pretty good. I think it was much more useful to have that on S3 with its tapered edges, but still from time to time putting it on will break the boredom of the same phone every day.
OT MaxDB, CD1, CD5, J5, GD96, ME45, T68i, X6, CX65, A925, E398, MPx200, X6-2, OT715, D600E, W810, M600i, BB8100, W880, N95-2, P1i, Ignito, W880, X1, MS1, MS2, TP851, XT910, GTab 10.1, SGS3, SGS4, SGNote 10.1, Nexus 7 II