I'm pretty sure I've commented on the original D50. The D50s doesn't appear to be any different other than the removal of the ESS 'hump', which was a solution in search of a problem since I'm not aware of anyone who could audibly hear what the hump contributed in the zillion ESS dacs that have it.
IIRC it sounds more or less like any other cookie cutter es90x8q2m Dac, which is to say, 'fine'. The power supply appears to be a basic linear one. I'd rather get one of the cheaper Ebay ones but that's just me. For the price of both I would just spend the extra $100 and get the Sabaj D5 which is in another league altogether. Or if you want to expand beyond the Delta Sigma world, the Schiit Modi Multibit.