I personally didn't like the mini keys, and a lot of space is wasted by those tinny speakers and the joystick. A lot of wasted area. Heck, I could design a better MicroArranger based on Korg's own Kross (and frankly I hope that does serve as the basis for a MicroArranger 2 in the future.)

The SD40 is a fully-featured arranger. If I were in your situation, I would look at a Roland A49 (used to be called the A500S.) Or, a 49-key Fatar CMK-149 if you can find one on the 'bay.