With $200, instead of getting a Korg MS, I would just get the Roland SRJV80-04 Vintage Synth Board. It has 255 different vintage synth sounds in there. Plus it keeps everything in one unit. The Vintage board, which came out 6 years ago still gets great reviews today.

Besides, put the Vintage Board in a XV5080, and you get 128 Note Polyphony instead of the 8 you get with the Korg MS.

The Infamous EPU.