This week I discovered that my wife's iPhone 4 (which she just received) has a weaker WiFi signal than mine. See image, this photo was taken with both phones side by side on the same location. (left is my iPhone 4, right is hers) The difference is as much as two bars (mine 3, hers 1) and I still have a WiFi connection in places where her iPhone doesn't. (on other locations the difference is sometimes 1 bar) We will contact Apple for this problem of course. But I wonder: if we only had my wife's iPhone 4, would we have noticed this? I think we would assume that the iPhone 4's WiFi range is not that big.