In other words, even the newer samples of the iPhone 4 (perhaps even that one for Sprint?) continue to have antenna quirks, but at least the latest and greatest seems to have addressed 'em. Hit the source link for the full report.
"Apple's newest smart phone performed very well in our tests, and while it closely resembles the iPhone 4 in appearance, it doesn't suffer the reception problem we found in its predecessor in special tests in our labs. In special reception tests of the iPhone 4S that duplicated those we did on the iPhone 4, the newer phone did not display the same reception flaw, which involves a loss of signal strength when you touch a spot on the phone's lower left side while you're in an area with a weak signal. (The iPhone 4, which is still available, continues to exhibit that problem, we confirmed in tests of new samples of the phone. Because of the flaw, we continue to omit the iPhone 4 from our list of recommended models, despite its otherwise fine performance.)"