Hello:
I have a SD5 to, and I had most of the previous models X1 HD and SD1(2). I would get it with the Hard drive, mine came with many styles not just from the MS series besides many midi files (I do not use them for performing, but, for learning tool is great).
I also would get the memory pattern/style expansion, if you use styles, that is a must, other wise you will be limited.
Like Don said, is a Great sounding instrument out of the box.
Hope it helps.
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mdorantes
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mdorantes