Thats a difficult one to answer. The main DACs that I have used in my system are:
1. Valab NOS DAC
2. Musical Fidelity V-DAC
3. 4x Wolfson WM8740 based ebay DAC
4. Audio GD Dac19 DSP
Besides this, I have a Goldenote Stibbert CD player, a Marantz CD6000 OSE and also a NAD C515BEE.
The Musical Fidelity was replaced in my system by the Valab (which was somewhat warm sounding and had more natural timbre). The Valab was replaced by the Wolfson DAC. The Wolfson lost the warmth and was a shade less natural sounding as the Valab. However, it was a leap up in resolution, imaging and dynamics. The Wolfson was the only one of the three that I flet was a significant upgrade over the Marantz. All the DACs were used with either a DVD player or Marantz CD6000 OSE or the Nad CD player as transport.
My next step up from the Wolfson was the Goldenote Stibbert. Compared to this, the Wolfson as well as the other CD players were a big step down. As a result, I stopped using all of them. The Audio GD was picked up initially for use with a pc in a headphone setup. However, I did compare it to the Stibbert. Whilst it is clearly inferior (particularly in resolution, soundstaging and the midrange), the Stibbert did not render it unlistenable. Whilst I have not compared it head to head with the Wolfson DAC (which developed a problem), the performance relative to the Stibbert suggests it is clearly superior. It is good enough that I use it as the source in my main system while my Stibbert has been lent out. This is something I could no longer do with the Wolfson DAC after getting the Goldenote. To me, the Audio GD represents the best of the Valab and the Wolfson DACs: resolution, imaging, dynamics etc while retaining a natural timbre. It does not have the extra warmth that the Valab had.
Sorry for the long post. Hope this helps.