Damn Namm, I'm happy with my SK880ps.
This is getting worse than cars & computers.
If a keyboard does a job for you why change ?
The average keyboard appears to be obsolete before you make the down payment on it.
The average musician will never earn enough to pay for his equipment (Murphy's Law ???)
Final up-grade ... sell equipment, buy stereo & play CD's. You can sit down, rest from carrying equipment, relax and you don't have to move a muscle.