I must agree that knowing the keyboard and how to use it to its optimum is a lofty goal, but not everyone is interested in that goal. Don't put those people who want new equipment every few months into a generality bin. I found by buying the G70 that its OS is still the Roland OS of past arrangers. More features have been added and it may be easier or harder to do some things, but it is the same old Roland OS. The same goes for the Yammies. Once you've played one, playing another is a baby step in the learning curve. So, there might be something to say for upgrading within the same OS. Otherwise, practice is separate from ownership and should not be generalized as Diki has done - wqay too extreme a view for my tastes.