Essential in your DS collection.
Compared with the outstanding original on the N64, it only JUST Falls behind.
I personally feel the graphics are better, the characters seem to have more detail, and of course there are new characters, all with their own pro's and con's, making them all unique. e.g. Wario is slow but powerful.
There are more stars to collect, 150 now, meaning there are new levels now, and objectives exclusive for the DS, so we feel that this isn't just a port, and makes the game feel more fresher.
Also, if you happen to have some friends, i definately recommend you try the multiplayer option, which is briliant. You basically just run around the level, collecting as many stars as you can, in the time limit. You can also beat up the other players to get their stars, which is absolutely halarious sometimes.
Also you can play the game with the d-pad or the touch screen, the d-pad feels comfortable but its hard to turn the full 360 degrees. I use, the touch pad, with the thumb attachment, it takes a while getting use to, but it feels better on the long run, as its easier to navigate the character once you have mastered it.
Overall, if you havent played the original, you must buy it, its an absolutely brilliant mario game that originally changed the world of 3D gaming. If you had the original, and didn't like it, i dont recommend you buy it, its not much different from the original, it just includes some tweeks here and there. But if you cant get enough of ol' mazza, buy it, it definately will keep you occupied for hours to come.