PA compared the performance of the iPhone 4 with the BlackBerry 9700 and HTC HD2. In most of the tests, the iPhone 4's performance was in the same range as the other two, but "consistently at the lower end".
Interestingly, the testers found that a certain grip on the BlackBerry caused as much attenuation as the worst grip on the iPhone 4 that didn't involve bridging the gap between its two antennas.
'Our tests indicate that the 'death grip' issue is real, and is worse for the Apple iPhone 4 than for other smartphones," said Simon Tonks, a wireless technology expert at PA. "The iPhone 4's radio performance was also found to be generally at the lower end," he added.
While the 'death grip' caused enough attenuation to prevent calls being made within a test chamber, that wasn't the case outside - which is where almost all normal people use their phones.
What about the Bumper? Please read on.
So no huge surprises there.
One curious thing is that around the time PA published its findings, Apple changed its web page about the iPhone antenna, dropping references to other models and focusing entirely on its own design and test labs.