The keys are great. Only minor complaint about the keys is key noise which is worse than Yamaha P-225 or P-515 and Roland FP-90X. But Kawai’s, in my opinion, are the best for practice. They are not “too easy” to play like many cheaper pianos that help you improve your muscle and your control but still the most responsive key in this price range.
Piano sounds are great. The main SK-EK piano sound is rich and warm, very good for solo playing. SK-5 is great for jazz and small band.
The features, by the way, are nothing special but just enough, which make sense for real life usage. Other sounds are good to have, usable, not great, but ti is not very important for this type of piano.
The speakers are decent but have some distortion in bass when open loudly. They are good enough for practicing at home but I wish they are more accurate.