You should get it, Meryl.
Although you don't get to see the full screen (at least I can't), the picture quality is pretty good.
It's great because this way, you don't have to stuggle with a GBA to play some really good games; you can play them normally on your TV.
The only thing I dislike about it is the 1 player thing. I'm not sure if you need something like a Game Boy Link, but it seems you can only play as 1 player. At least, I don't see how you can play with multiple people, given that the game supports it, that is.
All in all, I think your sis will like it, and you might, too.