Pros: Great sound, free case, volume range, twin outputs, amp
Cons: Volume control independent of Windows 7?, simplistic EQ
I pair this with AD-700's and cannot tell the difference between my previous Xonar DX...which is to say, brilliant. Great soudn.
Included is an "EQ" which is really - as far as I can tell - a bass boost. This is actually kind of nice for my AD-700's, as the +1 (on 0-3 scale) setting nicely augments the bass without overwhelming anything else. This is a pretty simplistic approximation of an EQ, but perhaps the best they could do.
-- Also, this allows for a FAR greater volume range than I had before. The E7 can get loud!
There are two analog outputs, which is a wonderful touch: you can plug two pairs of headphones in or, as I have it set up, speakers and headphones. Perfect!
Mixed Pro/Con: It seems the Windows 7 volume control doesn't affect the volume of music playback (in foobar2000, at least). This is a blessing and a curse: I can easily adjust volume in-game via the E7's volume buttons, but I can't even mute the whole system via Windows 7. I've gotten used to this very quickly, though, and it's a minor gripe.
Finally, it comes with a rubbery case that greatly increases friction/stickiness with surfaces.
Summary: Great sound, excellent volume range, twin outputs...excellent external DAC.
ps: I haven't used it for its mobile function, as I'm unsure of the connections needed (I don't have an iPod, and those are the most abundant connectors available). Not a concern for me *shrug*