After reading the title of this post again .... I'm thinking - why would anyone really want two (or more ) arrangers? I have a lot of gear in my studio, but they all serve a specific purpose that the others cannot.
I have the 9kpro as my main compositional/recording kb.
I have a Roland FP3 piano, because of the 88 keys and real piano action - mostly for clients that like to record on acoustic pianos.
I have the hammond XK2 organ - this is an indulgence because I got a great trade in deal on it. I LOVE the drawbars and leslie, and even if it's only for me - it's great to have in the studio.
The PSR2k is just for live work - it stays in my car all the time.. ready to go to work.
Lastly, there is "Old Faithfull" the i5S, just incase I need two setups on the same gig (happens a lot when cocktails are in a different room than the dancing)

If I ever get really satisfied with anything again - I'll get two, so one stays at home and one travels in the car. That way - I am not confused by which number registration, which organ patch etc....is which. I love simplicity. So far the Yamahas are close enough in design that I am in the comfort zone with them both, and I really only keep the Korg as an emergency backup.

Why do some of you feel the need to have several of the same kind of toy/tool in your setups? I find that I make better music when I'm NOT learning a new system or patch list. Isn't it confusing to have 3 or 4 of the arrangers on hand at once? Just curious....