Pros:
- it's cheap
- very easy to insert and use
- it has intructions booklet
- confortable for small hands
- solid wrist strap
- connector fits perfectly in the gba port of the nds lite (be sure to fully insert it or certain buttons wont work!)
- works great with all the flashcards

Cons:
None I can think of

Other Thoughts: I don't regret the absence of the guitar pick, I find the stylus more confortable to use because it's longer.
For now all the buttons seem working but I haven't played much with it so let's see how much they will last.

Bottomline: Absolutely get it! It's a must have item for every NDS Lite owner! You can't enjoy the fun of Guitar Hero without it.
A little warning, be careful of your wrists and read the instructions because if you don't hold it correctly you'll have a sore wrist afterwards, especially if you have little hands like mine.