I was just browsing through amazon and I saw the cover and I could have sworn that it was another Disgaea! I wonder if it is basically another Disgaea...
It has characters from Disgaea in it but thats about it in regards to similarity. Its one of those deals with multiple characters from different games. I heard it was pretty difficult so if hard games are your cup of tea go for it.
The strange part is IGN gave 2.5 or something to the game. But ,Its in teh GameFaqs' top 10 more than 1.5 week.
Niche title is niche. If you don't like Disgaea, you won't like this. As said, it can become ridiculously hard - to the point where the developers had to put up tonnes free DLC with items and equipment to make the game more manageable. But the real problem is that the game is glitchy as hell. It has loads of technical difficulties, which can turn people off.