I am using the n3 paired with a mojo to drive ca vegas. I really like the n3, its a solid little player. I run usb directly from the n3 to the mojo and it sounds great. Not 100% sure about whether its a direct bit perfect sound or not though, but I cant really tell an audible difference vs when I playback from my phone to mojo with bitperfect from usb audio player pro. I also really like the bluetooth functionality so I can stream from my phone. With usb, volume control and gain on the N3 do not affect anything, but the equalizer does still seem to work. When using usb to coax though, the N3 definitely seems to be doing its own processing too, as volume, gain, equalizer, etc all still work on the N3.
I will say though that when I plug the vegas directly into the unit I can hear fairly noticeable buzz/hissing. Less so when I use other iems (noble x, lz a4, it03). Dont know how it will perform with your other iems though, but if you plan to use the mojo all the time it wont be an issue.
Overall, I am quite happy with it and think its a good value. Just wish I knew a bit more about what its doing with usb out, and that there were no noise/buzzing/hissing with my vegas.