Roel -
My XD3 is three months old!! I have a 7 year old Alesis SR-16 and its display is fine (I know, it's not lighted). I have countless other products with LCD/LED screens that don't exhibit this problem. I have the XD3 connected to a Furman Power Conditioner on a dedicated grounded outlet and still it flickers and darkens. I don't consider this normal behavior and have never felt that a company's good nature to fix something like this with no questions asked represents quality. I have a buddy who bought a new Ford F250 truck and has has the automatic transmission replaced THREE times under warranty for free. I'm sure he doesn't feel that his truck is now reliable.
That's how I feel about my Ketron. As long as it keeps working, great. But if that screen dies during a performance I'll never buy Ketron again.
Just my opinion.
Tommy