It's also annoying if you have people trying to watch you play. I got to take a look at one in action earlier today, and if you're not in the exact place you need to be, you end up seeing triple. The system itself is very nice-looking, though. I like the screen size, and the design is very sleek, with an intuitive-seeming button layout. I'm also a big fan of the bluish color and the metallic finish, though I wish they'd given us more color options.
Personally, I'm happy with my DS Lite. It plays every game I want it to - so far, anyway - and is extremely portable. I might have to get a 3DS for Ocarina of Time, though. Not only is it the best Zelda game ever made (in my opinion), it's the game that got me into games. How can I not play it?