Decent...before you think about it too much.
The entire basis of it is the focus on the horror and reality of a school of monsters. The trouble is that while it does take advantage of the weaknesses of the various enemies he fights, it requires very specific circumstances to work. For example, he just happened to hit moka with a bottle of water. Inner Moka just happened to forget that water reduces her powers, and happened to not dodge what Tsukune threw at her.
Taking advantage of enemies weaknesses is all well and good, but the reality of things is that in the original series, after being injected with vampire blood and training with inner moka for a month, he didn't even notice a difference in his power level, yet he was later almost effortlessly able to take down a room full of mafia armed with guns and swords.
What I'm saying here is that while the idea of a human killing monsters is a good one, the circumstances required are too farfetched, and the power levels to different, for me to be able to take the story seriously.