Are you speaking of graphics? If so, I think the PSP has good graphics, HD screen, but I believe it is at a speed/mhz just below the PS2. I recall reading a lot about the PSP when I had one a few years ago. I would still have the PSP if it didn't start to fall apart on me. IMO the PSP is not portable, and is still a home handheld. Nintendo makes much better and reliable portable products.
Damn, I was posted in wrong thread, it should be in DS vs. PSP thread.
For graphic, DS looks like hybrid of N64 and PS1, let me to compare with Mario Kart DS and Mario Kart 64.
MK 64 course has nice and smooth, more looks like true 64 bit since characters looks not good as MK DS since MK DS course looks more PS1 or 32 bit to me because of notice on graphic with some pixels on track, that's hard to explain. I had tested with MK 64 from Wii Virtual Console and MK DS from DS.
Yup, PSP has nice graphic but their resolution is low than PS2 because it does help this games to be smooth with slow GPU, if PSP was true 480p then would make graphic looks like outdated and probably more laggy, Test Drive Unlimited on PSP looks more like PS1.5 since Test Drive Unlimited looks like PS2 but behind of Xbox 360. If Sony is going to introduce new gen of PSP with exceed of PS2's graphic, it would be imagine an different.
I feel that next-gen of Nintendo portable would be more likely between full N64 and Gamecube, can't wait until Nintendo is introduce about something.
Reduce of resolution and high texture graphic would be help alot for PSP, that what Sony was created.