I am very psyched for the CP88, I love the dials and switches.
The CP80 had those back in the 1970’s!
I am interested in how the CP88 compares with the P-515 as I want to purchase one of the other. Are the sounds the same? They have the same names (CFX, Bosendorfer) but someone says the 515 uses different sound technology. I don't understand the differences and don't really care if the sounds are the same but does anyone know if the piano and electric keyboard sounds of the CP88 are the same, or better/worse then the 515?
These are completely different products... each targeting a completely different customer.

The P515 above in its natural habitat... built-in Speakers, optional matching stand and pedal board.
The CP88/73 are Stage Pianos... XLR Balanced and TS Unbalanced Outputs, MIDI Master Keyboard Controller, PB and MW.

The CP’s are built for the stage in every aspect...
As to the sound, that’s for you to determine; words like “better/worse”, I don’t believe in — no one but the individual can decide what you like.