Steve McNally from Korg discuss' arranger composing on the microArranger. With a ton of musical styles and instruments to choose from, it's easy to create a great sounding arrangement from virtually any starting point. Whether you have a chord progression in mind, a certain combination of instruments, or just a certain style, the mircoArranger makes it simple to turn the music in your head into a reality. Steve also explains what makes an arranger keyboard a useful creative tool in your studio:

Here's a Japanese user uploaded video demonstration of the Korg MicroArranger's Midi player feature in "Song Play" mode.
This includes song selection, playing a midi song, how to enable/disable indiviual midi tracks,
as well as a demonstration of the keyboard's cool DUAL Sequencer. Sound begins at around 54 secs.

Man..., I think I just might have to pick this micro-baby up. It's one thing to see a trimmed le version of something.., but to see Korg take one of their current arrangers and only shrink it in "size" is amazing.

This would make a great addition to my Yammie S700. The micro keys wouldn't really bother me at all. The price is very reasonable too.