I bought this on Steam a few days ago and I've really enjoyed it so far. It mixes the RPG and Tower Defense genres quite well. I've also noticed that the developers are very open to feedback on their forums, which is lovely.
Pros (+) and cons (-) in my opinion:
+Excellent writing. The characters in your party deliver memorable lines early and often, and there are plenty of conflicts among them.
+Addictive gameplay with frequent player rewards
+Lots of endgame content and new game plus with hidden levels.
+Nice production values (sprites, music)
-Predictable, cliché plot
-Cutscenes are a bit ugly, especially compared to the nice sprites inside the levels.
-Grinding can make a lot of the challenges in the game trivial.
-Skill trees could be more interesting.
After I completed the game for the first time, I decided to try out "Hero Mode", which is a self-imposed challenge where you don't recruit any new characters during the game. The only way you can get through it is to set exp gains to 300% in the menu, and even then, it becomes incredibly hard once you start going into New Game Plus. I'm not sure if I'll even be able to finish it.