Korg PA-5X 61 International

In terms of sound, technology, comfort, design, this is a legendary keyboard.
But in terms of quality - all the buttons tend to break pretty quickly.
(The repair cost is not high, but it's annoying)
The ergonomics are very good, the interface is ingenious,
It's just a shame that the two stop/start buttons aren't on the bottom row close to the keys, and it's a shame that they aren't bigger, or in a more prominent color.
Another problem that bothers me is that there is no option to record in WAV format like on competing Yamaha keyboards.
But I highly recommend this amazing tool.