I recently went on a trip to Japan, and was faced with a choice on a new handheld gaming device to purchase for a friend.
So which is better? What are the differences?
First-off, I personally own a Gameboy Advance, and I finally chose to buy the PSP.
The reason for the choice was that I already owned both an iPod and a Gameboy Advance, but this friend of mine had neither... so for me the DS may have been a better choice, but only slightly.
Firstly the DS:
This little machine is slightly heavier than the PSP, but folds away neatly, it's more solid and resiliant, the games are cheap, load fast and can use older Advance cartridges. The screen has a huge surface and the touch screen is really nifty. The technology is way behind the PSP, but it is also about $50 less in price.
So this device has a huge advantage with current game availability.
It also has a good battery life (something I appreciate after my Japan trip on both my iPod and Gameboy).
This is a slick-looking device, but unfortunately the screen picks up scratches and fingerprints quickly. The teething problems with the first release has been sorted out, so no more bad buttons and broken pixels. It's battery life is poor, but is expected for the processing it delivers. It's really an amazingly fast little machine... way way way ahead of the DS. The games come on disc (UMD) and can hold a lot more than the DS cartrige, but loads slower (only slightly really) and are more expensive. The PSP seems pretty versatile though and you can easily get games and other software and upload it to the Sony memory stick (of which I have 512Mb and you can also get 1Gb now...).
It can also play movies from the disc (or from the memory stick if you (re-)encode and upload it yourself as well as music as MP3 (and some other silly format).
It's got WiFi and bluetooth (and I have already updated the firmware to a new version using WiFi without a problem).
The screen is brilliantly scrisp and clear, and even though it is smaller in size than the DS's two displays, it's still larger in size than a single DS display and about double or more in resolution than both DS screens combined.
Both these devices are good with playing WiFi linked games with multiple players, and the PSP can even 'clone' a game to a second machine allowing you to only need one copy of a game to play multiple players.
Overall the PSP is a well-rounded machine with a lot more potential growth. You will see a lot of 3rd party apps being released for it in the near future.
If you want something innocuous but reliable and fun nontheless, go for the DS.
Just my view.