If you need anything original in your anime, then this series will sent you running, as it doesnt have a original bone in its shonen body. Homunculus? Transforming weapons? People who tell their lifestory and/or their whole battlestrategy in the middle of a battle? A naieve but positive boy (Muto Kazuki in this case) that suddenly gets a amazing power, never wants to kill anybody and thinks the best way to battle is just to storm to your opponent with you weapon and scream hard? We've seen it all before and not only once.
On the other hand; if you like shonen series, this probably would not be that big af a problem and this series does have a few redeeming qualities. Firstly it is short and never overreaches itself in the story department; it has 26 episodes and it fills those without having any filler. Secondly it has some nice music: the opening got me pumped up every time and some of the battlethemes made the fights a lot more exciting. It also has a lot of humour and luckely doesnt take itself all that serious. The antagonist Papillon made me choke on my drink multiple times. https://www.youtube.com/watch?v=ye4htqWYk-w (Just had to post this.) Most of the other characters are likeable but not very special, with the exception of Tokiko. Tokiko is an surprisingly original female lead; she has a nice balance between aggressiveness ("I'll splatter your guts!") and rationality on the battlefield and the way she warms up to male lead Kazuki and his friends comes off pretty natural, though in the end she sadly becomes a bit too dependent for my taste.
On the negative side; when the series tries to be serious (which is in the most of the latter episodes) it is all pretty bland and cheesy, the animation is pretty bland as well, with a lot of speed lines in the battlescenes, and the story is very very predictable. So how much you like this series will depent mostly on what is your stance on shonen series; do you like them then you will probably have fun with it (as I have had), if you dont then do not bother; there is nothing here for you.