The main difference between DNC and SA is that DNC came out AFTER the PA2X was released (an OS update), so there aren't any samples in the PA2X designed SPECIFICALLY to leverage the new capabilities, unlike Yamaha, who have SA specific samples designed especially to work well with SA and SA2.
I am disappointed that, with Korg GIVING AWAY quite large sample libraries with the M3, high quality Oasys based stuff, that they haven't yet come out with some specific sampler loads to leverage DNC yet. It seems such a waste to have the capability, but not the content to show it off. Especially given that, unlike Yamaha, you CAN edit and create new DNC content and use the sampler to load it in...
How long has DNC been out now? It's over a year, isn't it? What is taking Korg so long? Make DNC sounds as good as the SA2 ones, and the Tyros3 has some SERIOUS competition.... Until they do, it's DNC... whatever!
