Here's my perspective...
I bought my Tyros4 for ME.
I could have easily gigged with a PSR-S910, or even a PSR-3000 or PSR-2000, and still do a good performance. I know this, because I actually used those instruments for my own personal jobs.
I could probably do just as good with one of the Korg or Roland arrangers.
But, when I play the Tyros4, I really like that extra bit of realism in the sounds, especially the SA2, and it makes me want to play more often because I like how the FSX action feels under my fingers.
I spent the last of my savings buying my Tyros4, and consequentially had to do without several other things, but the satisfaction I get back playing it and hearing that extra quality in the sound and the extra dimension in the response were worth the extra money to me, because I appreciate those attributes...they appeal to ME personally.
My audience may not know or hear the difference between an S910 and a Tyros4, but I sure do.
Both instruments in the video have their respective strengths and weaknesses...it just boils down to choosing the one that has the strengths you can't do without, and the weaknesses that you can live with.
Ian
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Yamaha Tyros4, Yamaha MS-60S Powered Monitors(2), Yamaha CS-01, Yamaha TQ-5, Yamaha PSR-S775.