Mini-review : fun to start, frustrating to complete.
If you are a Final Fantasy fan, you can probably skip this game. You are not missing anything by not playing it. At the start the game is fun and simple. As your characters get more abilities and the number of espers you can summon per-character increases, the touch screen controls really start to become a frustrating focal point of the game.
The pathing and collision of your armies make it difficult to employ any real strategy. Unit selection and targeting in large fights is very inconsistent. Just trying to rez a specific ally or cast a spell on a specific enemy is difficult because of the inaccurate touch screen or the inability to the target.
At the end of the game, the difficulty curve is too steep for the clumsy controls. If you could control your units as well as you can on a PC RTS it would be ok, but on the DS it was less frustrating to just mindlessly level until the missions became super easy.
There is hope for games of this types. A better gambit system, pathing, selection and targeting will go a long way to making the game more enjoyable. But for now, there are so many good RPGs on the DS I would move this one to the bottom of your list.