From my extensive experience with metal cases, unless it is a hybrid that incorporates plastic or polycarbonate the signal is impacted significantly. Some case Manuf. like Element Case and Devilcase, with their Type X. do a good job of using metal and keeping signal strength. Draco Ducati is useable as are the Spigen and Verus Aluminum bumpers but even these last three will drop calls in low signal areas. This bumper that is uninterrupted Aluminum around the perimeter will drop one to two bars and calls, unless the signal is very good at a location.
I agree, I wouldn't have tried all those metal cases if I didn't think they were the best looking and best feeling case. The case your looking at looks great.
looking at the video it looks like the sides are bowed and at the end of the video I see the top at the connector doesn't lay flush with the phone. The package it was shipped in is the most flimsy I've seen. I'm surprised it wasn't damaged in shipping. You get what you pay for. At that price I would be concerned.