How does it handle the bigger resolution?

As far as I can see the Turbografx is 256×239 (most games) and the DS 256x192. So there is a loss in the vertical, wich is sad.

Not that this is a huge problem. I finished megaman 2 on my DS, and the NES have a higher resolution to. But I opted for no scalling, so I could not see all the screen.