The UD100 is a 16 bit DAC while the Hifimediy is 24/96. For better detail retrieval I would go for the Hifimediy, but I have no experience with it. I'm running on the UD100, yes the price point I'd very low compared to other DAC. ClieOS had compared it with the Udac (or Odac? I'm not so sure) and they almost perform the same in terms of performance.
The UD100 also trumps the DACport just so you know.
Yes it works with the S3.
You don't get better detail retrieval by simply going from 16/48 to 24/96 though. Here is a good article to read about: link.
Edited by ClieOS - 11/17/12 at 8:06pm