The Tyros 2 is one of the easiest to navigate from new, but if you wish to edit it, so as to make it exactly what you want, you will most likely have to use the supplied PC software and a computer.
Another advantage with Tyros 2 is that the amount of third party styles that are available off the shelf dwarfs any other manufacture.
The Korg takes some getting into but is extremely flexible, also the Korg can load Akai samples, (Which gives you access to the largest sample library on the planet) so it will be quite easy to add specific sounds.
Also have a look at the Roland G70 and the Ketron SD1, which are also in the same price range, and have there own advantages and disadvantages.
Regarding sound quality, forget about the technology used, and see which board suits your ears. (If third party styles/samples can be loaded, try these as well)
Finally, depending how critical this is to you, please remember that the Tyros 2 only has 61 keys, whereas all the other boards mentioned have 76 keys.
Hope this helps.

Bill