Feature:
Simple is the best. No LCD touch screen, which saves electricity. Nice action on the hammer weighted keys. A little light compared to others but that suits me.

Quality:
I nearly throught it's made of solid steel. Super heavy, but I'm quite sure it can endure some abuses.

Value:
Overall, a reasonably good studio piano/controller for the money.

Sound:
Considering the price range, and forgeting about all the useless synth, guitar things, I think the sound set is quite competitive. Especially satisfied by the triple grand and strings presets. Depending upon personal tastes, however, the mids may be considered just a little thin for the piano sound. But I am used to playing huge piano sample libraries so it might not be fair.

Ease of Use:
It's not as straight forward as that you can throw the manual to the trash right away. That's mainly because of the simple digit display but you can get used to all the tricks within a couple of intensive hours reading the manual and experimenting.

Support:
Asked a question yesterday and Kurzweil got it answered today. For those with Windows Vista, mind you that the current version of the USB midi driver is not workable on your OS. Kurzweil said they are working on that. You have to do it the old way, using an external midi interface.