People are entitled to their opinions - and personally, I found the PSP to be a waste of my time. There are dozens of games, and yet only a few of them are any fun. I found this to be because of the ambitious 3D system and quirky controls. They didn't design the controls well enough to handle a 3D environment.
The GP2X has it's faults too - you move at the speed of the community, or you forge your own path. The PSP scene is pretty dry though, usually just having odd-ball apps and games which are really either limited in nature, or really doesn't excite me (crappy little minigames, etc). There are some cool things like video streaming (albeit crappy quality), or Wifi radio... but not enough in the scene of being a stable homebrew device. There is a lot of work to get the PSP running homebrew in the first place, and even when you get it running - many apps have speed issues, or bugs.
I'll stick with my GP2X - PSP is too big of a stretch for anything, mainly due to the expensive accessories (memory cards... 0_0), etc.