FWIW: http://daringfireball.net/2010/06/4 Partial quote: "There are two widely-reported problems with the iPhone 4. First is the issue surrounding 3G reception and hand placement on the device. Theres no doubt that this is an issue for many but I think a minority of iPhone 4 owners. I havent been able to duplicate the problem on mine, though. Sometimes, but rarely, I can make it drop a single bar, but I cant duplicate the drop to No Signal that many others can."