DAC1 or DAC1 USB?


I have decided to try out the DAC1 in my system. Does anyone have any experience with both versions of the DAC1? I have been told by Benchmark that a few things were changed from DAC1 to DAC1 USB but I find it hard to justify a 30% increase in price especially when I do not plan on actully using the USB option at least for now. Any thoughts? Thanks in advance.

My very modest setup:

NAD (5 disc changer)
Stratos Amp
Harbeth 7ES II Speakers
Rotel 1055 (used as peamp, looking to use the DAC1 as a pre and dac)
kego
The USB is connected to a computer of course. And the same album (ripped lossless into the HD) was used to compare.
INTO A DAC1 of course. Come on, guys. Are you messing with me? So far the only DAC mentioned here is the DAC1 and its USB version.
It just occurred to me I did not put "the" in front of "usb and coax" that might be the reason for losing you.