Good question, made me really think.I may be the odd one but to me an Arranger is a preformance tool. I do enjoy playing it at home and can get into some serious jams with the organ section and sometimes learning a new song. Being my "work" keyboard I just have to have a backup so I have two BK9s One in the studio and one downstairs in a closet ready to go.
My goto for playing at home has become my piano. It just makes me feel more engrossed in the music.
That and the fact I,m just too lazy to learn and reprogram a new board. Thats why I envy Donnie who can jump in and adapt to a new board quickly. Oh and also I hate onboard speakers and 61 keys IMHO and again its just me so nothing against orhers who like these things but those features just don't say professional keyboard. OK also the money because I'd have to go for two down the road but I can buy anything I really want.
Good luck and I'll be following all those who are getting one (or two!)