Yup - seems clear: independent testing shows the iPhone 4's signal strength is within normal ranges, but at the low end. So in combination with independent testing showing the iPhone 4 holding calls ahd handling data at consistently lower signal levels than other phones, you get what most of its users report - normal performance.
Just because PA Consulting don't know there's more to an antenna than a dBm number, doesn't make them right. Now of course I'll get derided for being a fanboy, blind to the truth and devored to the cause. But that's apparently the cost of understanding basic physics.