Oh, let's see.
Cuts off a part of the beginning of every track.
Sound tick noise in Gapless during track play. (at least we pretty much have Gapless finally)
Very slow interface and boot up time.
Also, a soft "tick tick tick tick" noise in the left channel with some IEM's. But that might just be an issue with mine.
I experienced the first and last issue only. They are not related to UI. boot up time is reasonable for me. If I consider the SQ I get from this DAP, these issues become trivial. IMHO