I haven't heard/used those two, but in general I'm not terribly impressed with Fiio. Personally, I would look into something like the iBasso D-Zero. But that's just me.
I will look more in to that one. I picked those to look at pretty much because they are already confirmed to be working well with the Nexus 7.
If I may, it depends on your price range and where you would be using it. I'd say the E17 if it's for portable use. I just loved that little gadget when I had it. It's also nice as an all around DAC (work/home).
For desktop, however, I have the Music Streamer II and highly recommend it.
It's for portable use mostly.