Both are from 'aristocratic' families, both are ambitious, but Alec is only ambitious to get what he wants like it is a game while Angel feels he can't live without Tess because he loves her.
Differences: Alec gets what he wants by force and doesn't consider feelings. Angel broods about whether Tess will want to marry him and pursues her out of love. Alec is driven only by his wants; Angel is thoughtful about what he wants in life. Alec is unkind towards women, Angel is considerate.