From what you're describing, I think you're after something that you can gig with.
Kurzwell is not something you want then.
Too damn unreliable.

Try Yamaha or Korg keyboards. Such as Yamaha EX7, Korg Triton and may be Motif.
Don't expect them to be easy to use right away. With almost any synth there's a learning curve and some manuals to read.

-ED-