I too prefer the other digital inputs over USB and the regular input would depend on the DAC/source in front. I'd take my PWD going Line-in anyday over using the stock DAC. The DX100 didn't do it for me if it wasn't acting solely as a digital transport.
Glad you like the 8610, perhaps it has a nice synergy w/ the FX700 for you. Not my cup of tea personally but it's good to have options especially w/ various phones.
Even with my Custom Hybrid IEMs I still prefer the 8610 for general music. I won't be able to listen to my music for as long of a period of time without getting fatigued on 209 so its a no go.
Edited by lee730 - 8/4/12 at 12:47pm