What is it?
The teenage successors to two clans of technique-wielders called "Kekkaishi" spend their nights exterminating demons ("Ayakashi") from the sacred land upon which their school is built on.
What's good about it?
I'll start off by saying I haven't read the Kekkaishi manga so I can't compare the anime production to the original. I tend to think anime series should be based on their own merits anyways so it shouldn't really matter for this review.
The plot is basically one story arc that goes full circle, providing us with a conclusive ending. For the fighting shounen genre this is nothing less than a tour de force. Most of these series feature one of these problems: many arcs of the hero going up after the ultimate vilain, only to have to face an even stronger vilain afterwards(Samurai X, Bleach) or the heroes fight the ultimate vilain over and over again, only to have him survive somehow and return to fight them, sometimes in a different or evolved form(Inuyasha, Dragon Ball). To be fair, those series were all considerably longer than Kekkaishi, but the effect is refreshing nonetheless.
Kekkaishi also has a nice, large cast of characters. The main characters do a fairly good job of rising above the stereotypic mold of characters that is quite common to the genre and offer some surprising depth.
What's bad about it?
Many of the Ayakashi are of the minion variety, quite undistiguishable the ones from the other. The first dozen episodes or so are peppered with filler stories, mostly revolving around other students at their school or friendly ghosts (lame!). I'm not too excited about the whole kekkai technique in general. It seems a bit too defensive to be exciting, though this aspect improves as the series progresses and the characters get better at wielding their powers. The main characters fall into the stereotype trap at times. I've grown weary of the simplistic "I want to protect everyone important to me" and "I don't want to see anyone get hurt" statements.
Kekkaishi isn't breaking any molds or stepping out of the box. However, those accomplishments aren't the goal of shounen series. Shounen series are about exciting confrontations between likeable heroes and sinister vilains. These series are considered a success if they can provide you with that without containing serious flaws, and under that criteria, Kekkaishi makes the cut. At 52 episodes, Kekkaishi isn't the commitment of other epic shounen series and leaves you relatively satisfied.
FYI- In the coming days I intend to give you the basic outline of my exciting fall lineup. Also, my next review will be the excellent comedy, Hayate no Gotoku!