I watched the video linked above and while it is someone speaking Chinese (I think) the whole time I think and never does much other than showing the case at all angles (I was hoping they would take it off at some point) and the guy does hold up a 3G or 3GS beside it and they have the same number of bars, FWIW (not much, I know). Would have been nice to see numerical signal and a test on teh same phone with it on and off, but at least it did not seem to block all signal entirely.
It's korean not chinese