There's no one aspect of Hyakko that really sticks out as being unique or specifically well done, but somehow the show itself comes together very nicely and I continue to find it oddly comforting to watch, or even just leave on in the background while I work. There's a certain unusual quality to the pacing and audio which I believe plays a large part in this.
The characters, while not really deep by any stretch, are each handled fairly well and are diverse enough to create plenty of opportunities for fun and chaos. While much of the show revolves around the antics of the hyperactive Torako, the show itself proceeds at a very casual pace. It's difficult to put a finger on what it is about Hyakko that I find so pleasant. It's not iyashikei inthe traditional sense, but somehow I get the same feeling from it, and I really enjoy that.
If you enjoy school comedy, iyashikei, or slice of life, then I encourage you to take a look and see if Hyakko works for you.