The FP-5 "partner" can work as a basic arranger but is limited compared to a real arranger..No variations[rhythm] with in a selected pattern..Not friendly in real time , looking for another pattern, or changing tones within a split...
What it is though ..a great digital piano with above average sounds...If you need arranger features on accasions, the "partner" will work...But it won't replace a dedicated arranger in the same price range..