I guess it depends on whether cost is of ANY consideration or not. At the moment, I'd be inclined to say the S910 is the best 'all round' Yamaha, simply because you can buy TWO of them for less than a T4...
OTOH, perhaps a used T3, bought from some poor sap trading it away to get the marginal improvements a T4 will provide over it, if you can talk him down far enough (and, as desperate for whatever Yamaha have JUST brought out as he is, you might be able to get a HEFTY discount
) could be the 'best' all round...
BTW, if you are Indian, the best choice would be (if restricted to Yamaha) the S910, too.