If you can move past some difficult controls, SM64DS is quite enjoyable!
Unfortunately this game is not without flaws. The controls are without a doubt the worst aspect of this fine game. 1) You have to press Y to dash, which is really crappy because you are automatically using both thumbs just to run. This makes performing a long jump more challenging because you have to use Y to dash and then hit R+B in unison. In the original game, you pressed up on the control stick and then Z+A, a task much more simple. 2) The camera is not so great in this game. I did not mind changing the camera with the c buttons in the original game, but the problem that I have in SM64DS is the fact that you have to use the touch screen in order to change the camera and have I already mentioned that you already need your thumb to run and jump. Therefore, it is pretty much impossible to dash and change the camera at the same time. This can cause some major slowdown. 3) Finally, the D-Pad is not quite as good as the joystick, but I do realize that the DS does not have a joystick and I think Nintendo did the best possible job with it.
Besides those couple of flaws, Super Mario 64 DS is really a great game that I enjoyed thoroughly. The game is not extremely challenging to beat, yet it is challenging to obtain all 150 power stars. Once you get use to the controls, you'll have a lot of fun with it.