Consumer Reports has reviewed the iPhone 4 and the news isn't good for Apple:
It's official. Consumer Reports' engineers have just completed testing the iPhone 4, and have confirmed that there is a problem with its reception. When your finger or hand touches a spot on the phone's lower left sideâ€”an easy thing, especially for leftiesâ€”the signal can significantly degrade enough to cause you to lose your connection altogether if you're in an area with a weak signal. Due to this problem, we can't recommend the iPhone 4.