Indeed, in Tested's testing some of the phones actually surpassed their promised talk time: the Samsung Captivate logged 354 minutes over a promised 350, and the iPhone 3GS had an actual talk time of 330 mintes, half an hour longer than the 300 promised minutes.
But the phones that had the loftiest claims also disappointed the most. The Motorola Droid 2 had the longest actual talk time of the six phones tested—465 minutes—but it also had the highest promised talk time of 575 min.
The biggest discrepancy, though, came with the iPhone 4, which promised 540 minutes but only delivered 382. Update: Tested's math was a bit off: the iPhone 4 promises 420 minutes of talk time. Hey, at least it was an improvement over the 3GS. For the full results, head over to Tested. [Tested]