Consumer Reports finished their testing and concluded that they could not recommend the iPhone 4 due to it's reception issues in a report posted today.We reached this conclusion after testing all three of our iPhone 4s (purchased at three separate retailers in the New York area) in the controlled environment of CU's radio frequency (RF) isolation chamber. In this room, which is impervious to outside radio signals, our test engineers connected the phones to our base-station emulator, a device that simulates carrier cell towers. We also tested several other AT&T phones the same way, including the iPhone 3G S and the Palm Pre. None of those phones had the signal-loss problems of the iPhone 4.
They also suggested using some sort of tape to place over the gap where the antenna is getting interference as a way to stop the signal loss or get a case. They will be testing out cases to see if it helps any in a follow up report.
Consumer Reports does recommend the iPhone 3GS if you want an iPhone that works without tape, however they state that the iPhone 4 had the best screen and best camera in their latest ratings.
