I'm about ready to do a throwdown between the Piston and thr NuForce 770X. One with a Beryllium alloy dynamic driver for $20.00, and one with a wideband dynamic driver for $25.00.
Sources are an unamped Sony NWZ 475, an unamped Rockbox'd Sansa Fuze, an unamped ipod Touch 4 with EQ 10, and the FiiO X3.
Files will be 320 mp3's, since only two out of the four sources can play FLAC.
music will be a shuffled selection of classic rock, pop music, metal, and the debut SKREW! album.
Comparisons and results coming within the next hour or so...