I've got an alu bumper case, a DNA case on my 5S. I had a similar one for my 4s and never had any problems. But now I notice a dramatic decrease in strenght of my WIFI signal at home with the case on. When I take it off the strenght is basically the same as on my iPad. So is there a Faraday problem here and I suppose it's the same with other metal bumper cases?
The reason I love this case is it's design and I can have the phone stand on its side on a hrd surface for selfies, time lapses etc. etc.
Any advice on a non metal case I can use in a similar way ( having the phone standing on it's side)?