I am in the same boat, playing my T3 for 12 years now and still working like a new one, never had any hick-up.
I would not sell my T3 for less than 1500$ (which is less than the price of a new SX700).
Tyros have large buttons, well lighted, with sliders, much easier to control during live play.
The smaller boards use up/down buttons instead of sliders (I have played many of these at friends house), pretty slow to control during live play.
Even if I get a new Genos, my T3 will be my backup for gigging. Many friends of mine want to buy my T3 once I get a Genos.