The biggest difference you will hear will be between the later devices and the e270 (v1), since it is running with a completely different processor.
The earlier v1 e200 devices sound pretty decent, though most folks can readily pick up on the differences when they step over to the newer players. The functions of Rockbox are quite popular with v1 users, as saratoga can attest, and enhancements continue, even for the later Sansas.
As to the reported differences in sound quality with the various current models, these differences are indeed subjective, and more subtle. The new devices are pretty close in sound quality, with the largest differences being overall features (size / controls / battery life).
µsansa
