They are all fine toys! Own them all! Each has different uses.
My RIO 800 MP3 hardware player has 4 hours of music on it. All for exercise (cardio).
Used my Nomad Jukebox with TA and HD570's at my computer this morning. 150 albums in one small box.
At the doctors office waiting room I took out my MD and small headphones. Listened to my tunes and waited.
Now, I am at my computer again, listing to a new CD from Mapleshade Records on my SL-CT570 and TA and HD570 phones.
I don't use cassette anymore. With really good phones it does not match MD or jukebox or the 570.
For my portable use, which is all the above, I do not expect perfection. Plus, the more toys, the better!
Only thing I don't use much is my Philips eXpanion 103 MP3/CD player. That does sound ok though, especially through line out.
Of course, the MP3/CD unit in my car gets a good workout. I have a few hundred albums on a few CD's.
As far as loading speed goes, which the Firewire units have. So frigging what????? I don't spend much time loading. Sorry. I load usually once and that's it. I don't change my tunes on my jukebox much. When I do load the jukebox (HD/MP3), the time taken for loading is not the transferring to the device, but the ripping and conversion of CD's. I don't trust a crashable computer with my music collection. It's all on CD's.
All my portable devices sound good through my Total Airhead and HD570's or 7506's.
And my bird Belle finds the 570's the tastiest.