Anything played through youtube has that, "compressed/distorted," sound like that. Its terrible what youtube does to music, as compared with a CD and a beautiful hi-fi speaker setup.
That said.. I'm not sure what the product is.. Did they sample digital pianos? Weird.. or it is some sort of physical modelling of digital pianos? Still weird.. Or have they created three brand new, "digital pianos." Not such a bad idea, imho..
However, if they sampled real pianos.. mmm.. they didn't do a bad job. sounds ok here that's all... does it sound so much better than the free version of, "true pianos," found in Sonar X1.. maybe.. it just might. I quite liked the sound.
Youtube definitely sucks for audio though..