macmini spdif out vs. usb

thanks for the response guys, i've been doing alot of reading the past few days, and this makes sense. I will pony up for the usb option, piece of mind is certainly worth an additional $300. Nothing worse than wondering if it could just be a 'little' better....

Well, you guys make some great points. My system so far is krell 250m monoblocks going to nht 2.9 speakers, so am a little concerned about the overly analytical sound. I'm pretty sure I want balanced outs of the dac, so should probably do some more legwork on figuring out the dac options. So far i have done a little reading on:
wavelength brick
apogee mini dac
grace headphone amp

I know that benchmark has a 30 day audition, pretty sure i can get that with the apogee, if I can swing that with the wavelength i might give that a try a the same time.