Chris.
I have heard both, and I guess this comes down to my last post, yes you will get the same sound out of each, and lets not kid ourselves here, neither will be winning anything for a HIFI product, they both sound middle of the road through a hifi.
1. But in terms of quality the ipod wins hands down and it works seamlessly with itunes. This means you can have half of them in lossless, half in MP3, or the whole lot in AIFF, or only one album in AIFF and the rest in AAC, you can have three albums on AAC 128, and 3 in 244, then you can have 10 albums as lossless. you get the picture.
2. You can set playlists and favorites from itunes, and use itunes to to sort out playlists for you, for instance all music created in 2004.
No other software I have seen allows this functionality.
3. You have access to the music store, 750,000 tunes to pick from, download and its straight on the ipod.
4. The ipod works just fine as a storage device, I back up my documents folder to it. You can set this on an Apple to do it at a set time.
5. The ipod has the dock, the output on this bypasses the sound controls so it becomes straight source, there is nothing easier than to just have a spare dock on top of your hifi, bang it in and press random
6. You can use it with apple Air Port express.
The ipod is clearly a far superior product, both in function and design.
7. Digital output is not all its cracked up to be, it just seems here and else where the assumption is that it must be better, those of use with record decks have different views, and the output on the ipod dock is Line.
8. The ipod has just dropped by 100 quid.
All I am saying is don't assume the iriver is better just because its cheap and has digital out.