Recently there had been many problems regarding the iPhone 3G reception and speed issues (even leading to lawsuits). But, according to tests conducted by some geeky Swedes, they were able to prove that the iPhone's 3G reception is "completely normal".
They compared the iPhone against a P1 and N73. Though P1 was proved better in receiving signals and N73 in sending signals, the iPhone was left behind just by a 'negligible amount'.
The equipment used to test the device were the once used by FCC. Remember that the results of test are completely based on hardware and not software so we can always keep a small margin.