I received my Atomic Hybrid Composite (delrin) case today and did some testing. Overall the numbers look very good, but I do have some non-performance issues. To be totally clear all of my testing was done with a LuckyLabs wrap on the aluminum antennas of the iPhone and in the same place in my house, all within a few minutes. I get very consistent reception here so I expect field testing to be reliable plus or minus 2 points. The bumper tested is by Apple (legitimate). Testing was the same whether I left the phone untouched or gripped it as I normally would.