To those who dislike fighting/action anime, Yu Yu Hakusho will be nothing more than an uninspiring romp. However, to those that find the aforementioned genre palatable, Yu Yu Hakusho will be loads of less-than-fluffy fun.
To begin with, the fight scenes are not overly drawn out - an essential component of any decent fight-style anime. The individual fight sequences, although they occur often, don't generally last more than an episode or two. This is an especially endearing quality considering some of Yu Yu's fighting-genre contemporaries, the most prominent of which is Dragon Ball Z, a series in which intensely long battles can become intensely boring very quickly. Another refreshing attribute is that the outcome of fights here are determined as much by mindful strategy as they are by power-level. And finally, from Hiei's Black Dragon Wave to Sensui's Saint Light Spirit, the attacks and techniques used by the characters of this series are plainly cool. In fact they are among the coolest I've seen.
Another admirable quality of Yu Yu Hakusho is its characterization. The characters of this series are thoroughly enjoyable and play quite well off one another. The lead character, Urameshi Yusuke, is eminently believable as a "tough-guy-with-a-heart". Kuwabara and Kurama each fill their roles quite nicely as well. The real treat in characterization though is Hiei, the reformed demon who is initially seen as an emotionally frigid self-centered being. During the course of this anime, Hiei is revealed to be much more complex and warm an individual than his humble beginnings in this series imply. Plus the less-than-playful banter that ensues between Hiei and Kuwabara is quite amusing at times. The main villains of each story arc are also well designed and rather intricate beings, many of which are often difficult to view as explicitly bad or good (Sensui is a prime example here). Beyond its leads though, Yu Yu's characters are mostly only adequate, simply filling the roles they need to fill in order to move the story along.
As impressive as this anime might sound so far, it does have several detracting elements, and they are not insignificant. The first of these distracting facets is simply the title's age. Yu Yu Hakusho, made in the very early 90s, wasn't very visually impressive even during its heyday, much less so today. That is not to say that the animation quality is bad (it is not), but when compared with more recent anime in American release, it is quite obviously dated. That said, the animation quality does improve throughout the series. Also, the music here is mediocre at best, often sounding as if it was simply slapped on the back of the animation to make certain that more than nothing was present. In addition, the dubbed version of Yu Yu (of which I have only viewed on Cartoon Network) is mostly tolerable with the exception of Kuwabara, whose voice is more annoying than nails on a chalkboard. Finally, and most obviously, the plot is a little more than cliched. Though there are plenty of major and minor plot twists to engage the right kind of viewer, many will feel as if the focus of this series gets muddled at times. Indeed, plot development takes a backseat to fight scenes a little too often, particularly during the Dark Tournament Saga. I am especially disappointed that the romance between Yusuke and Keiko didn't seem to ever become more than half-baked. A bit more story and character development would have been invigorating; especially considering how well the first five episodes did at introducing us to the complexity and intensity that Yu Yu Hakusho was capable of.
In the end, despite its faults, Yu Yu Hakusho is a worthwhile view. It is not groundbreaking in any sense, but it is a fun diversion that will work well on many levels for fighting/action anime fans. It has enough of a plot to keep it from getting severely boring and more than enough action to please any Dragon Ball Z fan.