If budget is not a problem, then take the time to test at least one model from each of the major brands, on top of Kawai, since manufacturers use different keybeds, samples or technologies :
- Roland (RD700 series, FP series, etc.)
- GEM (Promega 3, PRP series, etc.)
- Yamaha (CP300, YPG series, etc.)
- Kurzweil (SP2X, RE series, etc.)
Since sound and keyboard feel is 100% personal, only you can decide which one will fit you the best. If I try to give generally accepted views about the particularities of the digital pianos from each of the above manufacturers, I would say that :
Kawai has the best reviews for the keyboard feel action, closest to a real grand. Piano sound is good, but not the best.
The keyboard action found on most Roland digital pianos is stiff and heavy, even though different from a real grand, so this is something some people love and others hate. The piano sound is rather marginal.
The GEM pianos offer a completely different approach in terms of sound, and wins over the others for things like resonance emulation, half-sustain pedaling realism, etc. But they are difficult to find, so service can be a problem if ever needed and their keyboard action is rather light.
Yamaha digital pianos are, just like their acoustic pianos, not for everyone. They sound very bright too, which is not always the best for classical. So it's a love or hate thing. Their keyboard feel is pretty close to the Rolands too, stiff and heavy, but different from a real grand.
Finally, Kurzweil offers a different type of piano sound, which is also again a love/hate thing. Their keyboard feel is closer to the GEM, being on the light side, but they offer more ways to edit whatever parameter you want than any other brand.
So as you can see, it's a matter of compromise, since none of them offer all the advantages. So try at least one of each brand yourself and see about the keyboard feel and the piano sound, then select between certain models from your two favorite manufacturers.
Have fun shopping and take your time.