Don't wait for the next new thing. Get what you can afford NOW. Time's precious, and you've got grandkids to entertain!
My take on the two

remember, I'm picky)
*I like the speakers on board
*While the stifness of the keys is better on the Ty, the downward throw is longer on the 3k, and I prefer that. I get more expression from the distance somehow. I don't really like either one, so it's a case of the lesser of 2 evils for me
*The usb in/out is improved on the 3k
*A used 3k will be easier to sell if you upgrade later. The home market is more into that type of unit.
* I believe the vocal harmonizers are equal, or at least REALLY, really similar in quality
So, for me .... the 3k is actually a better choice, even without factoring cost into it.