Wow. I bought a PSP just for this game and I'm not disappointed at all. The gameplay and graphics surpass the PS2 version. Replenishing energy with annoying pit-stops is gone. Now you can absorb unwanted weapons to gain lost energy. This adds a subtle strategic element to the gameplay. The PSP analog controls are also fantastic as are the camera views which now fully let you see your ship.
The only thing I don't like is the inability to view your medal progression without entering the 'Progress' menu. It is completely seperate from the 'Race' menu and unnecessarily forces the player to bounce between the two when choosing betweem races.
Everyone I've shown this game to has been completely floored. I couldn't be happier with this new Wipeout.