I recently posted an issue with my Charge regarding call quality (it was "solved", so I'm opening up a new post since I am now having the same issue again).
I purchased the diamond design silicone case at Verizon when I purchased my charge (plastic-type case). I was having poor quality with the charge; a loud, scratching static noise was produced on 50% of my calls. I removed this case, and I've had no call quality issues.
I recently purchased a new case at a Verizon store; the soft "rubbery" silicone case. At first, I did not experience call quality problems (I've had the case for about 5 days). Now, I'm experience the same "static" scratching noises on 50% of my calls. I have to hang up and call back to get a clear call, and this is becoming very frustrating. I've spoken with IT over the phone, and they have no knowledge of this issue. I am now removing this new "soft" silicone case to see if my calls will be effected.
This is a serious issue that needs to be addressed; of all things, call quality is paramount with a "phone". I need to have some sort of protection encasing my $300 smartphone, however, it appears cases for the Charge effect the call quality. I've read that other people are now having this issue.