Got it, installed it, removed it.
The good: It came in a Vapor Pro box with a zippered case, certificate of authenticity (!) and tool kit with foam rubber "gasket" pieces for lining the case in key locations. It uses small, blacked Phillips-head screws rather than the larger hex screws of the genuine article. The workmanship is pretty good-- joints are flush, anodized color is consistent (though I had a small defect in the color of the black piece in one spot near an edge), and the machined aluminum is smooth, though with slightly visible tooling marks on the small beveled surfaces when held at an angle to the light. The vendor on Alibaba offered to exchange the piece with the color flaw, but only if I returned it to him in China first-- something I was not willing to incur the cost on. It did not appear to affect my 3G signal or GPS functionality at all.
The bad: It significantly degraded my WiFi capability. Where I normally get a full strength signal in my house, I was registered half that with this case. On my second floor, almost directly above my Airport router, where I normally get three out of four on the strength meter, I got no signal at all with this case.
Any pics of the real vs fake? I'm interested in seeing how they copied it. I'm surprised it didn't affect your 3G or cell signal but did to the wifi - I thought its always hand-in-hand?