NISA released Disgaea 3 on the Vita some time ago. It had all the DLC goodness plus a visual upgrade. It was easily the version to play if you hadn't already played the game previously. They have done the same thing with Disgaea 4. Personally, I loved Disgaea 4. The more mature storyline and characters really fit with how the game played. Valvatorez is by far my favorite Disgaea main character and Fenrich is a great supporting character. The PS Vita version of Disgaea 4 is just like Disgaea 3's Vita remake.
Valvatorez is a vampire that has given up blood for the love of his life. He sustains his life with the most healthy fish of all, sardines. As the Prinny instructor it is his job to train the Prinnies of the Underworld to be the slaves they do not want to be until their penance is paid. Somewhere along the line, The Underworld ran out of Prinny outfits and a peculiar girl with a loud mouth joined his ranks. Determined to find herself, Fuka joins Valvatorez's quest to take his problems to the President.
The main story is a good one, arguably better than Disgaea 2 or 3. The subplots are really well written too. Fuka and Desco not only have their own set of missions, but their roles in the main story are great as well. In the Vita version there is also a new character, she adds something very new to the game and his/her personality is unique, much like the rest of the cast. I won't talk to much about this character though, spoilers and such.
Combat plays just like any other Disgaea game, there is Magichange with monsters, a wide array of skills to learn, and of course, turn based goodness. When you collect enough Mana from defeating enemies you can promote or reincarnate your characters to increase their stats. The character development in this game is crazy deep and you will spend more time planning out your characters than you will playing them.
As with any Disgaea game, there is a lot of replay value, getting your characters to level 9999, discovering Valvatorez's past as Tyrant Valvatorez in his own episode series, and the rest of the post game content like the Item World are all things you can sink your teeth into. The main story is rather short, but it is all about the Post Game with Disgaea 4.
The start is very slow and the game doesn't get super fun until you are getting close to the end of the story, so that can turn impatient gamers off to this game. The reward is well worth the slow pacing though. The humor can get a bit too “anime goofy” for my taste but that is the risk with Japanese games these days.
Disgaea 4 looks even better on the Vita and it controls wonderfully. This is a the definitive edition to play. I give Disgaea 4: A Promise Revistited a 9/10. You can get it either on PSN or in your local game store.