Witch Hunter Robin is a fantastically hip, cool show. Comparisons have been made with The X Files and [Vampire Princess Miyu], well there are plot relationships with The X Files, and a vague atmospheric quality remeniscent of Miyu, but Witch Hunter Robin stands on it's own as a mark of progress in the quality of anime.
The animation in WHR is a combination of CG backgrounds and traditionally drawn characters. The effect is somewhat more subtle than that of [Wonderful Days], but more pronounced than in ...(need good example!!)... Character designs are very good, and the overall palette is rather dark but not murky at all.
There are references in the dialogue (parrotted by a few reviewers) to Robin Sena's clothes looking like a nun's habit of sorts. This is ludicrous, she is a goth doll and she knows it, and the other characters pretty much treat her that way right from the get-go.
As many have said before, this is not a heavy action shoot-em-up show. The plot proceeds at a very leisurely pace that is entirely appropriate to the story that is being told. And the story is not quite as shallow as it has been described by some reviewers. There are plenty of hints even very early on that Robin is uncomfortable with the whole idea of the witch hunts, and a sesitive viewer will be surprised at the depth of detail and emotion that is conveyed with extraordinary subtlety.
Did anybody else notice that Robin pays for her first meal at Harry's with Italian Lire? That is the kind of detail that is sprinkeld all over this show. There is also a fascinating scene where the director of the STN-J lights a cigar using a very, very impressive lighter, and Robin is obviously thinking that it is a clumsy way of managing fire... and that thought is conveyed with almost subliminal subtletly.
That said, this show demands a huge amount of attention from the viewer, and that attention will be rewarded with some wonderful surprises.
The opening credits and theme are a small masterpiece on their own. Of course, that does not guarantee the quality of the show (case in point, [Real Bout High School] which had a great opening and then fizzled right out), but in this case it is a confectionery treat of what is to come.
So, in summary, don't expect much in the way of action, but a really gripping story told at a leisurely pace, presented in a lush atmosphere of light and shadow.