After playing it for an hour and a half last night:
Disgaea is without a doubt BETTER.
However, La Pucelle in itself isn't anywhere close to the bad range. If anything it's like Disgaea Jr. The story doesn't lend itself to as much wackiness and is more map oriented. The Dark Portals aren't as much fun as Geo Panels. It'll be easier to learn for first time players than Disgaea, so that may be a good thing.
If you liked Disgaea, you'll probably like this one. If you thought Disgaea was too complicated, you'll like this one. If you only like FPS games, you'll probably not like this one.
I'd give it a 7.5/10