Kantian ethical theory distinguishes three levels: First, that of a fundamental principle (the categorical imperative, formulated in three main ways in Kant's Groundwork); second, a set of duties, not deduced from but derived from this principle, by way of its interpretation or specification, its application to the general conditions of human life - which Kant does in the Doctrine of virtue, the second main part of the Metaphysics of Morals; and then finally an act of judgment, through which these duties are applied to particular cases.

When consequentialist theories are developed in terms of an equally shallow psychology of the good - such as a crude form of hedonism - the results can sometimes strike sensible people as revolting and inhuman. People can be reduced to simple repositories of positive or negative sensory states, and their humanity is lost sight of entirely.

Utilitarians are usually empiricists who think they can solve every problem by accumulating enough empirical facts. They do not realize that thinking as well as experience is necessary to know anything or get anything right.

Kant's description of most ethical duties reads more like a description of moral virtues and vices. Once we see this, we see that Kantian ethics is indeed a kind of virtue ethics, and that it does not "divide the heart from the head" (to anticipate one of your later questions) but instead recognizes the deep truth that reason and emotion are not opposites.

The picture of Kant as the 'theological Robespierre' or the "world-crusher" was first suggested by someone with whom Kant stood in a relation of philosophical disagreement but also great mutual respect: namely, Moses Mendelssohn.

There is a very common, though also very silly, picture of Kant according to which as empirical beings we are not free at all, and we are free only as noumenal jellyfish floating about in an intelligible sea above the heavens, outside any context in which our supposedly "free" choices could have any conceivable human meaning or significance. Part of the problem here is that Kant faces up honestly to the fact that how freedom is possible is a deep philosophical problem to which there is no solution we can rationally comprehend.

It would be nice, wouldn't it? if we could get comfortable about the problem of freedom. Kant thinks that we can't.