I think the sequel is awesome. I loved the original, but I thought the story mode was extremely lacking. I spent all of my time on the training and challenges. Luckily, they really improved it on the second one. The biggest improvement, in my opinion, is the ability to
save your game 
. Couple that with all the new monsters, heroes, GUI enhancements, etc. and you've got a great title! It's been the portable game I'm most excited about since I played the original around the time I started at NIS America. It's gotta be the most addictive PSP title I've ever got my hands on. So yeah, I'm hyped.
In case you were wondering, this isn't just to plug the sequel. I like it that much.
ロビーが解説していること。The lobby has explained.