I spent a few hours at a local piano dealer today playing the Yamaha CLP-645 and CLP-685, and peripherally the Yamaha NU1X and Kawai CA78. Once again, I was the only customer on a weekday afternoon, so they were happy to let me loose to test what I liked and chat in-between. Here are a few thoughts on my visit:
I went in primarily to test the NWX action on the CLP-645, to help determine whether the P-515 (same action in a less-expensive slab) would be a worthy upgrade. For the second time, I found NWX pleasant but not exceptional; I could not feel the escapement at all.
I was impressed with the GrandTouch action on the CLP-685. I know this has been described on this forum as heavy, weird, etc., but it grew on me the more I played. Yamaha describes it as "firm and crisp" and that's exactly how it felt to me. It was easy to play close to the fallboard and escapement was distinct.
The dealer had a poster with a cross-section of the GrandTouch action, in comparison to the NWX/GH3 action on lesser Clavinovas. With the visible part of the white keys at 15 cm, I estimated NWX/GH3 at 21.5 cm and GrandTouch at 25.5 cm. Thus validating Yamaha's claim that the CLP-685 has the longest keys in a digital piano.
(Yamaha says that the length of GrandTouch keys is exactly the same as in their S3X acoustic grand. I checked this out and it seemed accurate.)
The pedal of the CLP-685 was better than that of the CLP-645, having a lighter feel at first touch, then heavier, just as in an acoustic grand. The CLP-645's pedal felt more linear, with seemingly less travel.
I did not focus as much on sound as I did on touch, and almost always used the default CFX concert grand voice, which I like.
I briefly played the NU1X and liked its action with the clear escapement, but its keys were distinctly shorter than the CLP-685. Looked gorgeous in its polished ebony finish!
Also played the Kawai CA-78, the GF2 action of which I had loved on an earlier visit. The action is obviously completely different from the GT of the CLP-685, being much lighter, but I didn't care for Kawai's default piano sound.
The dealer is getting an N3X in a few weeks and will call me when it comes in, though he knows I'm not going to buy it. He feels that he might tempt me into an N1X (same action), which he offered to me at a discount from its MAP of $9,000 (MSRP $11,000). I told him that is unlikely, but will check it out, nevertheless. I think they like me coming in to enliven their day ... Ha!
The bottom line is that these are all good pianos; it's purely a matter of personal preference. As "oneilt130" said in a recent thread:
... once you decide what features you want and have a list of DPs that fit those criteria nothing will replace going out and testing them, preferably multiple times. Then get the one that you feel the best at. For me it was the NU1X but for someone else it could be the Kawai CA98 or Roland LX708. One thing I do feel confident it saying is that there is no universally accepted "best for everyone" piano in this price range.
For reference, I played the following pieces to test:
Bach: Gavotte from French Suite 5, BWV 816
Mozart: Fantasia in D minor, K 397
Beethoven: Bagatelle in A minor, "Fur Elise"
Chopin: Nocturne, Op. 9-2