I used to think the iPod sounded natural, detailed with great separation and soundstaging before I've had more diversity in my listening experiences.
It's the level of experience that matters more: a person who's had more experience with top quality DAPs, like the iMod, or even the NW-HD5 (a great representation of Sony house sound), the expensive Kenwood line, iPods, iRiver Hxx/Hxxx series, vintage CD players, and various Samsung and Cowon products, would have a more qualified opinion than somebody who's only have had experience with one Cowon product and an iPod.
I'm not disqualifying personal opinion, but I would take the word of a portable audio enthusiast who's been in the market for a while instead.
I haven't said that the D2 sounds bad. Nor is it analytical, it's just a cute little portable player with great memory potential and aesthetics that have been overhyped by a chain of newbies who say: "Cowon products are highly regarded here, you should get those and ignore all other comments."
Edit: An amp would need to give the iMod it's sound characteristic, but since the level is simply above the mainstream portable market, it would need a broken, or a terrible amplifier to make it sound worse than a D2.