Hi and welcome to this Forum.
I don't know about the Casio, but I had a D 70 many years ago; it was the model that followed the D 50, but was very different from it, in that had a soundset derived in part from the U220.
I remember a really good piano and strings patch that cut very well in a mix, but the other sounds somehow lacked personality and Roland was unable to replicate the success of the D 50. I remember that I really liked the 76 notes keybed.
Since I am rather picky about the sound, I remember that I decided to sell it after listening to the individual waveforms through headphones and noticing that they were sampled with a lot of noise (hiss).
However, like I said, the keyfell was really good and I know that some people still use the D 70 as a master keyboard.
Hope this helps.