Anyone using an Apogee Mini-Dac?

Recently, I ripped several hundred CD's uncompressed to the hard drive of my Mac G4 1.25 GHz Powerbook and played it through my system by taking the headphone OUT and splitting it into the R & L inputs in my pre-amp. Sounded suprisingly good. Better than CD's played on my $400 Denon DVD player. And that was from a Headphone out! Now, I have bought an M-Audio USB Audiophile DAC. This allows me to use the computer as a digital transport which feeds a digital signal to the DAC through the computer's USB port. This makes an incredible imrpovement to what was already pretty darn good sound. The M-Audio DAC cost around $175. Now, I'm curious. Apogee makes a similar USB DAC called the Mini-Dac, which goes for around $1,000. Anyone had any experience with these?
Apogee is a highly respected brand and a recording industry standard for A/D and D/A conversion. They're not the only product out there, but their offerings should sound very good in their price range. I haven't heard many raves for the M-Audio Audiophile DAC. I'm pretty sure the Apogee would be a huge improvement. You might also want to consider your preamp and speakers/headphones. Are they capable of portraying the difference between the $175 DAC and the $1000 DAC? If not, you might want to save you money and enjoy the M-Audio DAC.
My pre-amp is the Meitner Emm Labs Switchman, my amps are Levinson 436 Mono-blocks, my speakers are Monitor Audio Studio 60's, my headphones are Sennheiser HD580's. That part of my system would be capable of showing the differences. I am thinking the source, the Mac G4 and i-tunes
(CD's ripped uncompressed using AIFF), would be the limiting factor, if any.
I recently heard a computer based system which used a Tube DAC made by Scott Nixon of Winston Salem, NC. It is a straight DAC with no filter and no upsampling. I did not understand how the data is clocked to the DAC.
I have noticed some people looking for this DAC. I don't have direct experience with it, but for what it's worth, I do use an Apogee DAC in my main system, and I'll say a little about it in order to give an idea of Apogee sound quality.

My unit is a DA-1000E-20 with its matching power supply. There is no USB input. Its sound is really excellent. Lots of energy and presence, very involving, brings me one level closer to the music. A small trace of congestion and hardness in the upper midrange on complex passages, but this is only compared to very much higher end gear like the Cello Reference converter, the Ensemble Dichrono pair or a Linn CD12. It is also more forward-sounding than these.

Other than Apogee gear, I have been told very good things about the Presonus Firestation, an ADC / DAC / mixer which interfaces with a computer via FireWire.
Finally broke down and bought the Apogee USB Mini-Dac. Sounds waaaay better than the M-Audio USB Audiophile. Huge improvement. Full, rich, detailed, deep wide sound stage -- all the good stuff -- and allows me to use the computer and hard drive as a high quality Juke Box.

I've not used the Mini-DAC, but my recomendation at that price level from my experience in music production would be to grab the Mobile I/O ULN-2 from Metric Halo.

You'll have no need for the +DSP feature, and while MSRP on the base ULN-2 is $1,195 you can find it from any number of online pro-audio retailers for less.

I've used their 2882+DSP interface as an input interface to my DAW, and I've been EXTREMELY impressed with the quality of the DAC, the mic pre's could be a little better, but they improved them in the ULN-2.

Anyone considering the Apogee Mini DAC (or already has one) needs to hear it running on batteries!

I am running mine on (8) "C" cells at the moment and it sounds dramatically better this way! Once I see how long the run-time is, I will decide if I need to go to some larger batteries.
RE: Batteries for Mini-DAC

I have no idea how you're doing the 8 C cell trick, but some other battery options would be:

OEM Site down just now
but this site seems to carry batteries that look identical

These look heavy, but top notch?