I haven't tried all the presets on the sx900 VH, but I did find one that suits most of the "stuff" I do--Country Rock.  The VH would be usable for me.  I'm definitely NOT a power singer.  
Maybe it's just me but I think the VH is improved over previous PSRs, but maybe it's just some better presets.   
I think it might be better due to better DSP's and output.
Plus better presets.
At least that is what was mentioned regarding the Genos when it came out.
I use the PSR-970 for small background type gigs and the VH is certainly sufficient.
Eric
 
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Genos, PSR-S970, TC Helicon VoiceLive3, Mackie 802-VLZ3 Mixer, 2 Bose L1 Pro16, Electro-Voice ZXA1 Subwoofer