The anime does move somewhat slow at the beginning, but after awhile the pace picks up. The first 26 episodes are somewhat much more lighthearted than the latter 26, where much blood is spilt.
The most prominant problem with this anime is the horrendous amounts of melodrama that take place between the two main characters. They change from loving each other to "not loving each other" so many times in the course of the anime it becomes very meaningless by the 40th or so episode (or earlier).
Still, it's a very good anime and worth watching.
FINAL SCORE: 85