Just to let you know guys, I was lucky in finding a very good priced half-new 2600RS (completely maxed out) for 750 euros. I bought it, now I have the K2500XS as a master controller. I have to say the KDFX makes a HUGE difference (and triple mode as well!).
I am a Kurzweil "funatic"

The motif ES impressed me in some way, I guess it is a user friendly keyboard with very decent sounds, but I couldnt find one at an affordable price. But, honestly I feel that I have all I need with the addition of the maxed out K2600RS.
The previous owner told me that VAST was too complex for him

So, I told him... "you probably should buy a Korg".

Cheers.