Yamaha US now has the S550 on their site..., and there's an audio sample (I would assume this is one of the onboard demos). Sounds pretty darn good.., check out some of the eastern styles http://www.yamaha.com/yamahavgn/CDA/ContentDetail/ModelSeriesDetail/0,,CNTID%25253D5021560%252526CTID%25253D205500,00.html
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.