Okay, I recently bought Crisis Core for my PSP. I played it and honestly...it's my favorite game! Genesis rocks. Honestly, no offense to you or this site, but Crisis Core vs Kingdom Hearts is no contest. Crisis Core kicks KH's ass. The only game I know that can stand up to Crisis Core is the .hack//G.U. series. Gameplay it wins, while storywise Crisis Core wins.
Well I do love Crisis Core, but I don't know if I personally would compare it to Kingdom Hearts. The games are for two different consoles. I think Crisis Core is good for a PSP game as Kingdom Hearts is for PS2. Anyway, I really loved this FFVII prequel. It made a lot of stuff clearer and introduced some pretty cool characters. The game itself lasted me a good while and is re playable.
I loved CC and it totally completes the full storyline of FFVII. When I played FFVII, I was confused of the past. Now it's clear. The best game on PSP.