Well, I would suggest that until you play the SK-3 in question, you don't know if you'll like it. Voicing and regulation sure have a lot to do with the tone of a piano, but sometimes there are inherent qualities in certain individual instruments that are just part of the tone.
The Kawai "2" model, going from the KG-2 to the RX-2, the GX-2 and the SK-2 has always been their 'go-to' domestic size and lots of pianists and teachers love them. Sometimes the "3" model isn't that much better, and some people don't find it better enough to justify the cost difference.
For me it would come down to the individual instrument and not the model designation.