Its a question of subjective taste and not fact, and varies according to listener, room, piano preparation, mic and speakers, eq, and time of day, etc. YouTube is useless as a reference.
Yeah, no kidding. "We will play this $600 keyboard and then play this $5,000 digital piano. The difference is amazing!"
Uh, no. Because what I hear is limited by the sound capabilities of the laptop or mobile device I'm using to watch your YouTube video. And my ambient noise. Duh.
Many members here own decent headphones. I myself have a few headphones and A/B test these comparisons. Please also consider that if you have used your headphones for years (for making music) you already know the characteristics of your headphones (your eras learn the characteristics of your headphones by listening to the same song/arrangements on different hardware).
The sound quality of the video is decent. It's about 99% real and the 1% is not noticeable to my ears.
The descriptive/characteristics of these instruments can be scientifically/mathematically qualified and quantified. All needed is to compare the frequency spectrum of both instruments and see the stereo images produced by both. Brightness means more presence in the higher end of the frequency spectrum.
Yamaha samples are very authentic! But CFX or CF acoustic pianos sound bright in real-life.
I believe Kawai sits between Yamaha and S&S. It's not too dark and not too bright and budget-wise it is as affordable as Yamaha. I also prefer Kawai over Yamaha for jazz for several reasons.
S700 sounds far better than CFX IMHO:https://soundcloud.com/yamahasynth/s700-grand-piano
I own a MOTIF XF and S700 is the sweetest piano sample I have ever heard from Yamaha. It sounds a bit like SK-5 in my MP7SE.
I picked this one directly from Yamaha's website about CP88:
[ S700 ] Built by Yamaha master artisans, the S700 is a handcrafted acoustic grand piano with the power to cut through dense arrangements and the control to remain expressive in solo and sparse settings. A staple from the S90 ES stage synthesizer and MOTIF ES music production synthesizer, the S700 remains one of the most popular grand piano Voices available today.
Just read S700's description:
with the power to cut through dense arrangements and the control to remain expressive in solo and sparse settings
Kawai EX Grand and SK-5 sit perfectly in any mix with minimum EQing effort and they sound fat and voluminous. It's difficult to describe them but they have a special mellow punch to them that shines in the mix.
Unlike the S700, Yamaha's new CFX and CF voices lack this punch. Even with EQing, you won't get there. Bosendorfer has the punch to it but it just doesn't sound nice like S700.
The S700's problem is it really old, not 88 keys sampled, few layers, and very short samples.
It would be interesting to see who likes S700 on their CP series more than CF and CFX?