Mother 3 was great if you played the translated ROM, but it was never officially released outside of Japan. I dont think it's fair since most of the world cant play it legally.
Dawn of Sorrow is just another great title in the insane DS library. I don't have time to sit here and make a greatest DS games list. That would take hours.
It's certainly a matter of preference. I love the GBA Warioware games, the DS game sucks. Same for Rhythm Tengoku. No Metroid, no F-Zero. Animal Crossing is grrat and all but I could never play Wild World again because of New Leaf. The DS Zelda and Star Fox games suck.
We definitely could make a case by case arguement for both systems, though. Don't get me wrong, I love the DS, too.