This information comes from Nintendo Power…

“Yes, definitely [improved graphics were a priority]. We wanted to do things that were not possible on the previous handheld. For example, I’m developing Nintendogs + Cats, and I really wanted to realize the sense of fur on the pets.” – Hideki Konno

Trust me the 3D is nice but the graphics are fantastic. I still hear some people compare it to PSP or a little better. How about you compare it to Game Cube.