Other than raw sound, to be honest I'd probably put the S910 as a 'better' PURE arranger than the G70, assuming one is going to put the styles in it that suit you best. OS-wise, it's got a LOT going for it... multiple drum channels, synchronized arranger and SMF play, multipads, break/fills, Mega guitars with guitar optimized NTT's, SA voices, the list goes on and on. In fact, the root cause of my campaign to get a 76 PSR910 is because I REALLY want one!

The fact that the G70 covers the SMF and live play bases better (and I can't GET a 76 910!) still makes it the better choice FOR ME, but I have NEVER simply dissed Yamaha's across the board, and really wished I got some brownie points for that once things get heated up! So much of what I say POSITIVE about Yamaha's gets forgotten completely once the 'red mist' comes down on ITS' 'fanboys' (apparently, we are ALL those, now ) in response to the slightest critique...
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An arranger is just a tool. What matters is what you build with it..!