In response to the original question, the advantages I have found for the 890 over the 980, after about six weeks of use, include: the 890 is smaller and lighter, making it much easier to hold. The 890 buttons have a very smooth action giving the unit a much nicer feel in the hand during operation.
However, I have a number of press-to-hold macros that generated a sound file at the start or end of the macro, and the 890 does not allow for sound files to be played; every key sounds a short chirp when pressed. This is disappointing.
Overall, however, it is a much more elegant unit.