I don't own one...yet...but for this christmas I'm getting one myself WUAHAHAHA. The price is cheaper than psp, the time you can use is longer, MULTIplayer and online games are great! of course the DS is one million times better than that sony crap! and yet the games to come are even better (right now there are only a few good ones)...
I think the Ds had too much faith placed in the novelty of the touch screen. the games may be innovative but the majority of them bearly use it, jsut for minor things ike the maps. I own a psp, and I was surprised with it's power both with games and with other ypes of media, the picture on the umd movies is crisp and clear, and the games are far batter graphical calibur thant he DS ones my only problem is the lil joystick thing, its just annoying.