Sure, there are important distinctions between Theravada and Mahayana Buddhism. The major relevant one you may have in mind is the regard each tradition has for figures called bodhisattvas. In Theravada, bodhisattvas are are just nice but somewhat deluded human practitioners who try to save other suffering beings from the fate of rebirth. In Mahayana, bodhisattvas, though they begin as human practitioners, transform themselves through their enlightenment and compassionate vows into veritable Buddhist angels. In Tibetan Buddhism, for example, the Dalai Lama is considered the incarnation of the bodhisattva Avalokitesvara. But, even in Mahayana, bodhisattvas are not considered gods; they didn't create the universe, and they don't rule or ethically judge anyone--they just help people out.
Yeah, I know about the Bodhisattvas. But my impression, especially after being to China, is also that there is a difference in practice, although perhaps not in theory, in that the attitude taken to both the Bodhisattvas and to Buddha himself within Mahayana is more "God-ish" in all but name, whereas the Theravada are more clear-cut and hard-line about there being no Godhood involved.
But I'm no expert on Buddhism. I'm thinking that Mahayana is sort of like Catholics with Madonna. One could argue that the treatment of the Madonna in Catholicism is that of a Godess in all but name, and that this is in line with Catholicism's general approach of including the saints and the Pope as important figures, as opposed to Protestantism which is more hard-line about God being the whole deal.
