Ian judging by your reply I sense that your feelingness for the S910 havn't changed at all even after the T3 or T4....the honeymoon is wearing off and you start to realize the S910 is more then adequate in many ways FOR NOW...nothing wrong with that....
Actually, Donny, I will always think of the S910 as a terrific mid-range arranger, with excellent "bang for the buck" value, but, I think I have found the instrument I want for my personal use.
I've downloaded the complete Tyros3 styles, and now I have basically a Tyros4 AND a Tyros3.
Perhaps the Tyros4 won't appeal to you once you've played it and spent some quality time using it.
I do know that
it appeals to me...more than the Tyros3 did, and more than the S910...some of the reasons are tangible, but some are hard to explain...basically, it just
feels right.
I start doing clinics next week, so I best get more familiar with this beauty. Time for more tea!

Ian