Two reviews, one from a Head-Fi'er:
NuForce Icon owners / discussion thread
Ignoring this weakness in noise floor (this is only audible if your earphones are very sensitive), on the music..
ran a few evaluative tracks through, monty alexander's once i loved, joan baez's diamonds and rust, norah jones - new york city..
very good! by far one of the most decent headphone outputs i've listened to. comparing to the $750 IQube headphone amp, the synergy and clarity is just as good, and soundstage's pretty impressive, no longer compressed. sheffield lab's percussion was good, it was as though my earphones suddenly was more able to push more air.. (although its armatured)
As a bonus, Icon has a decent headphone amp. This is not a cheap trick, Icon employs a discrete circuit for the headphone amp. Again, the sound quality is very good, this is no mean feat for the headphone out of audio amps.