So many great choices when it comes to 88 keys, but I, too, think the PX560 is among the better choices in many respects. I used to own a Casio PX330. An excellent action (as subjective as it can be, it is a very solid keyboard action) and great piano sounds at only 24 pounds. The Yamaha P515 looks promising, but at 48 pounds, I won't consider it as a gig instrument. The PX560 is 26 pounds. Just recently I purchased a Numa Stage (28 lbs) by StudioLogic. I should have purchased the PX560.

Anyway, any 88 key controller paired with either vArranger or the SD40 would make a great 88 key arranger.