BLOOD DIAMOND is a pretty good film that should have been great. Its biggest problem is pacing; the film is too long by at least 30 minutes, all in the middle. It's very plot-heavy and could have been more effective with a better writer. The film is also very violent, with many on-screen deaths. At some point, you have to mentally turn off the violence and think "it's only a movie." A better film could have done a lot more with a lot less.
Leo is pretty good, although his accent seems to drift through three continents in the first three scenes, but he has the most well-defined character of the bunch. Jennifer Connelly proves that she is not only beautiful but is politically correct as well, and does as well as possible with a predictable character.
Djimon Hounsou tries his darndest but his character is so one-dimensional (angrily defiant) that he does not seem real. It doesn't help that there are far too many coincidences in the film for it to be believable, either.
This is the type of film that's perfect for DVD as you can get away with not paying attention the whole time.