I got an iPhone 4 on launch day. Like many I've noticed that when I grip the phone in my left hand in certain geographical locations without a bumper, the signal drops. I've dropped a call twice because of it. However, adding the bumper pretty much took care of that problem. Now onto what I think could be my problem. At home I have an AT&T 3G Microcell. When I had my 3GS it worked beautifully. I had 5 bars throughout my condo and never had call quality problems. Now, with my iPhone 4 (even with bumper) the signal bars go up and down like crazy. I thought that perhaps it was just the signal readout that Apple will be fixing in their update. However, I was on a lengthy phone conversation last night and put it on speaker phone, so I could monitor the signal without even holding the phone. It turns out it still did the signal fluctuation, and actually when it got down to 1 bar, the other person started breaking up. When signal went back up, they told me they couldn't hear me for a while. This tells me that it wasn't just a readout problem, it's a legit reception problem. Keep in mind that all this while I am sitting 6 feet from the Microcell. With my 3GS I was able to actually be quite a distance away, even outside, and maintain up to 4 bars without any sort of breakup. Has anyone else here experienced this with their iPhone 4 and Microcell? Seems to be completely separate from the death grip problem. Do you guys think I should go to the Apple Store for a replacement to see if I have better luck with it? Thanks in advance.