DS for all the reasons stated. PSP is not worth my time or money and theres so many problems I have with it. The whole thing is held together by magnets, so if you drop in on say a carpeted floor, it can very easily break.

And with people saying the DS isn't as 'hardcore' as the PSP I laugh at you. Play MPH against some of the top players on the GameFaqs forums (or me, I used to be up there), play some of the top snakers at Mario Kart, go to Smogon.com and play some of them at Pokemon and play the new Contra 4. The DS isn't less hardcore because it doesn't have as many 'mature games' in its library, in fact I'd say its games are far more hardcore because of the easiness to have fun, but the easiness to find a really difficult challenge.

Or just micro up some CnC