They are too close in the areas important to me, for me to be tempted.

The only reason I would get a Tyros5 is if I needed 76 keys, but, for my way of playing, which is arranger style play, 61 keys are just right.

As far as sounds go, I've got lots of excellent sounds to work with already on my Tyros4...judicious use of the T4's effects and filter/brightness can give me what I want.

Ian