As a DS owner I have not been very impressed by the games for the DS in general.
I have found with the DS that my favourite games tend to be based on the classics. Like Mario Kart, or Mario DS. This game is something far ahead of anything seen on the DS thus far. As a proud owner of Mario and Luigi Superstar Saga this game was long awaited by me. This sequel is a very strong advance on the origional.
This game includes a fun, puzzle based, and RPG like storyline, and most aspects of this game are extremely enjoyable. Although graphics were not advanced at all from the previous game the gameplay is still fantastic, and I really like the battle style, which includes a turn by turn sequence, allowing you to avoid and counter attack throughout.
The touchscreen is not used very much at all, (which i liked) and the controls were based very much on the ABXY buttons, which is a nice change.
All in all a very strong good game, and I highly reccomend it.