I have the ODAC/O2 and I did a comparison with the X5. For portable use, yeah the X5 would be better, but the ODAC/O2 sound way more transparent to me. The X5 sounds coloured in a direct comparison: more bass, slight treble roll-off, funky upper-midrange/lower treble thingamabob, narrow soundstage. I hear a bass emphasis too. The X5's DAC portion adds some warmth compared to all the other DACs I have at hand.