They say that the modern electronic keyboards are weighted to feel like a conventional piano. And the sound is such that it's difficult to tell the electronic from the regular piano.
The one Vika is using here is an older model concert Roland 700-series that she's been using for years. I've seen her post where, as a classically-trained pianist, she prefers a conventional piano, but you have to admit that it's got a great sound.
I'm not sure what piano Matsui is using here (the keyboard on top is a Yamaha) but I have seen her perform with a Casio, though I'm not sure which one.