WARNING: The greed Gumi has in here is legendary.

The Bad:
Not only do they have the loot box summons, but to get them to max level you have to summon multiples of that unit (about 14 times for a 5*).  As if that wasn't bad enough, to get the gear for your characters you have to spend even more money on loot boxes hoping to get their equipment. This once again requires duplicates to evolve them to the highest star rating. 

The Good:
The gameplay is unique for the mobile market as the game plays akin to Final Fantasy Tactics/Disgaea/Tactics Ogre. So if you have enjoyed those you will enjoy this too.

The story is fairly well done past the very "ugh" first chapter of "is this kid really this gullible?"

The game does have Auto mode, but it will not use skills in any efficient matter which I like. The AI will use your biggest AoE skills to kill a single monster when it could have waited a turn and hit 3-4 with it. You can get away with it for clearing the repetitive missions, but on the Hard Mode event quests manual control is required. 

For better (or worse) there are events always going on with new characters being introduced. This leads to a fair amount of free premium currency to spend. Just be sure to use it wisely, some of the units are near useless due to their niche nature vs one a week later that can cast an instant AoE from 5 squares away.