CyberGene P.S. If you still like the NU1X for its sound and feel but can stretch to the N1X, I believe it's just the perfect instrument where you won't have any complaints. The NV5 is slightly cheaper and I believe it has a very good upright action which won't suffer from loud note "issues". I personally am rather cold about the Kawai samples though.
I played all hybrids several times, but mostly with headphones. JustMusic in Berlin had them all in their exhibition. Right now (I assume due to the supply problems) there is only the NU1X left.
I liked the action of the NV-10 most. It's feels exactly like many grands I played, but excellently regulated. I love that they implemented the real damper mechanism. The N1X was great too, but stiffer and harder (not necessarily heavier), so based on action alone, I would prefer the NV-10(S) over the N1X.
Regarding the NV-5 and NU1X I felt the same. I preferred the action of the NV-5 over the NU1X. The NV-5 actions felt like a more "grown" upright action with longer keysticks / pivot which made it more precise and even across the deepness of the key, regardless of playing far or near the fallboard. The NU1X felt a shorter, and again a bit shallower and stiffer. But it was good enough for me.
So action wise: NV-10 > N1X > NV-5 > NU1X
The sound system of the hybrid grands was disappointing. The NV-10 sounds boxy and the base is too strong. The N1X sounds a bit better, but not clear enough and I feel like the overall quality and resolution of the speakers is quite low.
The NV-5 was the best sounding digital piano I've ever played and closest to the experience of an acoustic piano. But the NU1X sounds really great too - both much better than their grand hybrids counterparts.
Sound system: NV-5 > NU1X > N1X > NV-10
And aesthetics: NV-5 > NU1X > NV-10 > N1X
Like you I like the CFX samples better than the SK-EX Samples. But both doesn't sound as good and organic as Pianoteq for me. As I play mostly with Pianoteq (and would use better sounding sample libraries like VSL if my computer was up to the task) this is not a deciding factor.
I also realized in the two weeks with the NU1X that even with the good sound system I practice and play most of the time with headphones because I don't want to disturb my neighbors. To play a piece for my friends and family the weaker sound systems of the grand hybrids are also good enough.
The reason why I initially decided for the NU1X were very practical. It was the most affordable hybrid with a real, good enough action, good samples and a great sound system. A Big Bonus was the integrated audio interface. I can play Pianoteq through the integrated speakers with only a single USB cable and it's a great experience, it sounds wonderful. The N1X can do this too. But as stated I play most of the time with headphones anyway. So the deciding factor for the next purchase should be the action, and I like the NV-10 actions the most. There is one problem: It's double the price of the NU1X…