Slytherin to the bone ! Cunning, determined, resourceful. Sometimes calculating and even manipulative. Heck, nobody's perfect - above all not me !
I read the excellent piece of "rant" about bravery/recklessness, ambition/power-hunger. These are the defaults of the quality actually. The quality pushed to the extreme. Ambition can be a good thing : it is wishing what anda want to do of your life - and giving yourself the means to achieve that goal.
The whole difference lies in the motivations and the purity of intention.
Well, there are hardly any of them left then. Most 'purebloods' just blast Muggles, Muggle-borns, Squibs, and 'blood traitors' off their family trees. (i.e the Blacks)