I had a Yamaha Clavinova which I had for 3 years until I bought my acoustic Petrof upright. Was very happy with it and thought the sound and action was very acoustic like. My piano teacher was nervous at first because unless the keys are weighted properly, you often wind up having an awkward transition back to an acoustic piano. I had no issues going back and fourth with the Clavinova. While I was told by another piano dealer that Steinway "endorses" the Roland digital keyboards as it's alternative to their acoustic pianos, I've never been able to confirm that was the actual deal. As for the Yamaha Clavinova, it's sampled sound comes from their Conceert grand so I'd suggest making sure you like the sound of Yamaha grands before considering.
I played a Yamaha Clavinova the other day and it sounded better than a number of Grands that I've played, I was shocked that a digital piano could produce such a great sound.