I had a PSP Slim (3000) and used CFW (Custom Firmware) on it to enable me to use questionable software which included homebrew (user created software).
The Slim was a good machine only problem I had was the thumb stick which I had to change myself after 12 months. Not really a problem but was a common issue with the Slim.
PSP Go came out which was purely downloadable content I decided to stop using the PSP's all togeather. Was not sure abotu the future of gaming for this plateform.
The new PSP Vita has touch screens and better thumb sticks x 2 which sets it up for some pretty impressive games in the future. FPS games being one of them.
If your starting new to PSP the Vita might be the go if not interested in CFW. It's not going to be cheap though with pricing as high as that of a full console.
Anyone else like to comment.