Pros: Detail, connectivity, unobtrusiveness
Cons: A bit expensive, sound through USB underwhelming
The c5i will connect to nearly anything and reveal detail. My old system - not only old enough to drink but old enough to suffer for it - was in comparison sludgy, fat and slow. I got rid of 70 lb of analog kit and replaced it with a 13 lb c5i and a Vortexbox on a fit-pc2. The S/PDIF connection sounds the best: the USB connection seems to suffer from power supply noise coming from the Vortexbox. Bit-perfect S/PDIF output from the Vortexbox provides detail that in some instances shows off tiny, beautiful percussion riffs or hall sounds and in others reveals recording artifacts or little noises that make tracks un-listenable. There is all kinds of headroom. The volume control is calibrated in arbitrary units from 0 to 100, and I have not had the system above 75 in my 30' x 17' x 14' living room. The sound gets clearer and more detailed as the volume control goes up, but there is no blast-effect of LOUD. Speakers are NHT 2.3s which are reasonably efficient.
The c5i is expensive - somewhere between human blood and Kopi Luwak coffee in dollars per pound, but that metric bothered me for about fifteen minutes. The thing just sucks you in. I have been, as the tired old saw says, "rediscovering my collection" every night until much too late from the purchase date until now, and that doesn't show any signs of abating.