Bismark is the magnificent bastard. He's a magnificent manipulator, and a right bastard. He was removed mainly because he wanted to crush the socialists in Germany, not out of any idiocy of the Kaiser's, and his whole foreign policy was 'Punch anyone out who threatens us.'
He unified Germany in what could be argued is the worst way possible. He totally left out the Austrians, made the French resent him for the annexation of Alsace-Lorraine, and the way it was achieved left no room for liberalization in his time.
That said, he's still a smart person, and did unify Germany, despite the above. He kept peace in Europe, for a time, though I doubt it would have lasted even if he was still Chancellor. All in all, not treated negatively enough in modern times.
Louis Napoleon on the other hand, is not treated well enough. Compared to the Republican government, he prevented colonization of Algeria, not wanting to just plop Frenchmen in native land. He renovated Paris, turning it from a slum city to the architectural wonder it is today by hiring that Baron guy whose name I forget. And he gained Savoy and Nice for France, and helped unify Italy as a bonus to that.
He was also too superstitious for his own good. The only reason he didn't invade Prussia during the Austro-Prussian War was because he had a kidney stone or something like some night, which he saw as a bad sign, and cancelled the invasion. He also had a habit of getting into grand schemes in an attempt to ape the first Napoleon, like the whole Mexican adventure, and even entertaining the idea of recognizing the CSA.
All in all, Napoleon III did a lot of good domestically for France, but on foreign affairs he was a very mixed bag.
