Haven't heard one but there's a long comparison piece in the latest online version of MacWorld. Here's one quote:
"Listening: The iPhone sounds as good as any iPod youve ever owned. Mine plays through the portable speaker systems Ive connected it to via the Dock connector port on the bottom of the phonethough the iPhone tells me that the attached peripheral is not supported and offers to switch the iPhone into Airplane mode to avoid generating audio interference. Like the latest screen-bearing iPods, it supports gapless playback so you can feel secure asking it to play the B-side of The Beatles Abbey Road or Brian Wilsons Smile without interruption."
Apple doesn't provide any way to get a digital signal out but there are modders who do it, at a high price. There have been several threads about that recently.
"Listening: The iPhone sounds as good as any iPod youve ever owned. Mine plays through the portable speaker systems Ive connected it to via the Dock connector port on the bottom of the phonethough the iPhone tells me that the attached peripheral is not supported and offers to switch the iPhone into Airplane mode to avoid generating audio interference. Like the latest screen-bearing iPods, it supports gapless playback so you can feel secure asking it to play the B-side of The Beatles Abbey Road or Brian Wilsons Smile without interruption."
Apple doesn't provide any way to get a digital signal out but there are modders who do it, at a high price. There have been several threads about that recently.