While I can't vouch for the specs, I have a lot of personal experience using Juli@ cards, both as a digital datastream source to feed into another DAC, and also using it's on-board DAC. And I found it can make a very satisfying, enjoyable DAC.
I'm gonna tell you a bit about my experience with computer audio, of which the Juli@ has been a constant and key participant. Bear with me, as most of what I'm going to say does not involve the Juli@ directly, but has a huge bearing on the sound you get out of it.
The biggest issue with the Juli@ is the computer it sits in. There are many formulas and techniques to improving computer-audio sound. I got involved with computer audio using the formula for the cMP/cPlay combo, which in its most optimized form, takes a Windows XP system, strips out components not needed for music playback and optimizes those left. In that process, you replace the Windows shell with cMP and use cPlay as the music player. It is best built on specified hardware, but the general techniques can be applied to most XP or later Windows computers. A computer setup this way does a pretty good job producing audio.
The original base cMP/cPlay setup specified the Juli@ soundcard, using only the digital section to feed an external DAC. But as I found out when I first set mine up, it played quite well through the analog section of the Juli@. I used it that way for over a year as I learned how to better tweak my setup & do physical modifications to improve both the computer as a music-playing environment and the performance of the Juli@.
Once you've addressed the software environment using the cMP/cPlay configuration and optimizations, the biggest issues with a computer for music playback are the noisy SMPS computer power supplies. I know that there are a number of good-sounding and well-reviewed pieces of audio gear that use SMPS's, going as far back as the Berning tube gear in the '80s. I am very happy to currently listen through amps powered by SMPSs. But power supplies are the heart of any piece of audio gear and have to be designed as such to produce good sound… and no computer power supply that I have seen or know of is designed to do that. One of the earliest physical modifications I made to my cMP/cPlay setup was to build a couple of simple 12v power supplies and use one to power the processor via the P4 plug on the motherboard and the other to power a device called a PicoPSU, which is a small device not a lot larger than your normal computer motherboard power plug. It is designed to be powered by 12v (initially for mobile computing) and provide the voltages and turn-on logic needed to run the computer just like your standard computer power supply. But it has a nice side effect of producing less electrical noise and hash and making the computer sound significantly better, if powered by a good 12v supply (or battery… but not the cheap and dirty SMPS's that are often sold with the PicoPSUs). Truthfully, any piece of audio gear will sound no better than its power supply… and powering my computer using a PicoPSU fed via a linear supply made the sound out of my Juli@ a LOT better!
I went on to do a number of modifications to the Juli@ itself, both on the digital side and the analog side, and also powering it seperately from the motherboard. While I'm not using the Juli@ analog section currently, the sound I got from it in that configuration, especially after the mods, was very respectable.
Part of why I tell you this is that being a part of the Bottlehead community, you've likely built some of your own equipment. And building a power supply/Pico PSU setup is definitely a LOT simpler than any of the Bottlehead kits. And as a DIY project, it will cost you a lot less than a separate DAC.
Your main resource for all of this is
http://www.cicsmemoryplayer.com/index.php , the Main cMP/cPlay page. In addition to describing how to setup & use a cMP/cPlay system, it includes links to the monster cMP & cPlay threads on the Audio Asylum, which are both large and filled with lots of good info on how to setup your computer audio system. It also has an 'Advanced' section that links to a number of specific subthreads, including computer power supply mods & Juli@ mods.
Another good resource is
http://www.mini-box.com/s.nl/sc.8/category.13/.f , the mainpage of the supplier of PicoPSUs. BTW, while they can be found on Ebay, some of the Ebay ones were found to be inferior copies, so I recommend going to the supplier or a reputable dealer.
Feel free to contact me offline via my profile email if you have further questions.
Greg in Mississippi