Summary: I love this game, but didn't own the ps2 version. I thought it'd be a good idea to upgrade to something more recent and get it on the psp. Another plus would be the added ease of playing with headphones. This version is a lot gentler on your thumb, and more forgiving with joystick direction making stages like #5 easier. For some reason, I found stage #4 on expert mode to be MUCH harder than on the ps2 (perhaps due to the design of the psp).
Summary: If you're a fan of Gitaroo Man and wish you could play it anywhere you go, then this is a good port of it. Gitaroo Man is my favorite game all time, but I do have a few complaints on this game. First, this may be resolved with the new 3rd gen PSPs coming out...sometime in the future, when the new PSPs can handle more movement, but for now with my 2nd generation PSP, some of the movement of the symbols on the screen become fuzzy and hard to follow.
Summary: I really liked this game when I started playing it. The graphics were cute and fun, the characters are odd and funky. And the tunes get into your head real quick. But here's the rub, the difficulty curve is steep, really steep. The first 2 levels weren't too bad but the third is near impossible. What I'm undecided on (as I've not played the PS2 version) is if this difficulty is just due the PSP controls/version or if the PS2 version is just as hard.