Just tested my Nova N3 with Sennheiser HD238 and could not hear any hiss. Touch screen is smooth, and UI is usable. However the only weakness which is being discuss in another forum for Nova N3 is the volume on N3 is low. Eg if i compare the loudness of iphone 5 and nova 3, iphone 5 can be louder in comparison. There is also an indication that there might be a firmware update after CNY to increase the volume of Nova N3 to its full potential. Hopefully this is true.
Now is busy with Chinese New Year so will write a review later.