Hey, I'm new to the forum (and this is my first topic).
I got hooked in here when I saw the debate about the PSP beign worth the cash, and I wanted to drop my two cents. I had both hand-helds, but I don't pocket-play anymore due job reasons and I better bought a home console... so there's no real preference for any of them.
Based on my criteria... both hand-helds have some power to hold, but the sales of every unit know more about this than the actual firepower from any gizmos these companies can throw and brag about. The PSP is capable of many things that it's enemy couldn't do at first: playing movies, music, d-photographs, emulating and whatnot. To top it off, adult franchises such as GTA and Tekken (also add CrapCom's hundreds of already-done-ports-of-fighting-games which at this rate, make me sick).
Everything at an elevated cost that should make you think... Is it worth it?
The DS is already able to emulate (except for PSX), with certain accesories is already capable of music, videos and photos. Everything at a cheaper price. Movies on UMD are not as popular everywhere as anyone might think them to be; with no plans on making them as flexible as regular DVDs (a.k.a. no compatible writers, no blank hardware to write on, no compatibility w/regular tv-sets and no feedback from big-retailers and even worst, movie companies who refused to use them due high-priced production costs and sales that wind-up disappointing).
(And don't start me with the battery power which made me want to smash my PSP many times it ran out during critical moments)... That's for sales... I won't discuss hardware. PSP and DS have shown users of how capable they're with their softwares (and it can be a matter of taste)... for me, Nintendo excels on many ways that leaves PSP waiting too much to be desired for being "more powerful" on specs.
Games are another deal which is a matter of taste. But I can argue about PSP's merits for adult-oriented games and sure-hits with old RPGs and those done-a-hundred-times-before fighting games. But that isn't innovation, compared to DS' library of interactive games that adds to the genres something new on each game... by the time I got Trauma Center, Phoenix Wright, Lost In Blue and many others hit the markets (the list is huge), it was clear that the balance between brands and quality is killing Sony.
What is quality? ... Good graphics? ... Better gameplay?
As far as half of the games I played on PSP went... they were pretty much the same stuff as before. Nothing felt really impressive, but that's because they don't fix what isn't broken, just use whatever formula sold well before. On the other hand, DS took risks to innovate... and now PSP's sales are pale compared to the DS ones.
Saying that I have no preference sounds like a typo at this rate... but the lower development costs combined with the chances of developers to innovate their franchises (Like Contra, who improved a whole lot compared to it's PSX and PS2 versions), adding newer chances and more succesful games (that don't need to be ported on the company's older home console) who later turn into well known franchises on their own, are giving you the obvious answer.
I'd like to add... Japanese imports at this rate, are so much better and hundred-percent more wacky on DS.