I have both, but I use my PSP more often. It's just that a lot of the games I have on the DS are "remakes"(I have pretty much EVERY Final Fantasy "remake" for the GBA and DS), and I'm tired of playing "remakes".

Sure, it may have a longer battery life by and large, however, PSP has Monster Hunter Freedom Unite(Portable 2nd G), it will have Shin Megami Tensei: Persona next week, I think next month Silent Hill: Shattered Memories will be out(even though many will say things like,"It's better on the Wii!"), it will have Kingdom Hearts: Birth By Sleep, Phantasy Star Portable, and it has the Playstation Network.

Most of the time, I use my DS coupled with Fullmetal Alchemist: Dual Sympathy as my alarm clock.

I like both. They are both good for different reasons. DS are good for interactive and mind games, whilst the PSP is great for movies and RPGs :D

My cat loves PSP.

still looking forward to getting a PSP

I also got both.....I'm using psp for my Music and Anime on my travel....it's sony...it's sound great....but the game too huge and complex although It's 3d point awesome...but Gameplay Sucks.......To play games I'd rather play NDS....
Now I'm just bought NDSI...few games with camera sound fun but I'm still waiting to buy PSP GO....How's about PSP Go...Is it worth to buy PSP GO now?

i also got both i mostly use psp for music there are not many games i want this year so i am not playing much

I personally prefer the PSP. Growing up from a PS background, it's hard to miss those games which are PS exclusive, such as Tekken or Gran Turismo. The bigger screen, and better eye candy doesn't help either. xD

I have both but play psp as i have gacked to play psx games:)

I'd have to say that although I have both, like it seems a lot of people do, I prefer DS over PSP. The games are far more interesting. I actually wouldn't have a PSP, but I ended up winning it out of a machine. You can't beat free!:)