PS Audio DL III?

Anyone out there using the PS Audio DL III? How does it compare to the DacMagic?

If buying a used DL III how can you tell what generation it might be? I see Stage 3 and 4 units listed for sale.
There are a lot of threads here in the forum that discuss the DL-III. Overall, very positive. There is only one generation, the Stage 3 and 4 units refer to the Cullen's stage III and IV modifications(Cullen is now Wyred 4 Sound), which take these units to a whole another level (and higher price).