Anyone have experience with these setups? I'm contemplating buying the Topping units new or trying to hunt down a used Emotive XDA-2 for maybe a little more $$. These seem to be the most talked about and reviewed units that I can find for their cost. I know the Emo has an additional optical and coax input and a remote which is nice, but that's about the only difference I see (non-technically speaking lol). Any thoughts or suggestions greatly appreciated. I use the Senn HD6XX headphones and will have a laptop and bluetooth receiver used as sources for music. Would also like to run dac through an external amp for bookshelf speaker play. Thanks!