Thanks Mac for your explanation of semi-weighted. I had naively assumed that it meant simply less physical weight is added to the keys than a fully weighted key.

I actually bought a Casio WK500 thinking that I could get used to the light touch. It has a "hard" setting which makes a small difference to the feel but I just cannot play the thing as a piano without sounding wrong notes. There also isn't much velocity difference between a light or heavy stroke. Am I right in assuming that the Kurzweil electronic key weighting system will be much better than the Casio?

Thanks
Tony