I'm pretty sure that they'll still go for the DS. While my PSP has been good to me, I still get ticked off at the controls, at times, especially when it comes to fighting games. Surprisingly, the fighting game with the best controls is Mortal Kombat: Unchained (Tekken: DR gives me trouble performing moves with exact diagonals, despite everything else being okay.), but I digress.
I'm watching the thread now, and I have to say from personal experience, the battery life lasts about 3, 4 hours tops with me, but even then, I play it in sparse periods of time, so it's somewhat tough for me to gauge. It's somewhat annoying to charge it up every few days, yes, but I only play for like 30-45 minutes at a time, so it'll last me a few days.
But, overall, the DS wins. The stylus can sometimes be a bit unwieldly, but innovation always plays a key part of impressing me.
Speaking of which, I'm kicking this to the handheld section.