I think GF would be a great addition to the PSP. Whom in my opinion is severely lacking quality games. I have a PSP, and I have gone through 3 of them so far. The first two that I have been through were exchanged under the manufacturer's warranty. The third one, I had bought through Sony as a refurb because my PSP had gone out of warranty.
The problem that I have had with my PSP's was the analog stick.
I use mine for movies on the go, music, and since my grandma doesn't understand the world of internet or email. I bring photos to show her of my cousin's children.
It was a good idea, but imo not very well thought out with functionality.