Please read the following (Jan 2003) thread :
http://www.synthzone.com/ubbs/Forum37/HTML/005528.html

YamahaUS answers more or less the Tyros has standard size keys..... and I disagreed very much.

I too had problems with the toy-ish keys as I was 'feeling' the Tyros.

Perhaps you should give the SD1 another try Dave ? The key-feel is perfect and with the latest OS a keyboardist HAS to love her

Roel