I have a DS, I love it for playing games on, particularly Sonic, Scrabble & Brain Training (though my brain age is far older than my actual age
) It fits in my handbag, and I sit in the car and play it. I use it less now I have an iPad, as the screen is bigger & I also have internet access on it.
If you go into somewhere like Game, you can get second hand ones for quite a reasonable price & you still get a years guarantee. My MiL has a DSi XL which has the larger screens, as she found the standard DS screens too small. Go and have a look / hold / try of one and see what you think.