Very few from the standpoint of his subjects. What appeals to a "modern" outlook is his efforts to create a what we would recognize as a nation-state, with a standing army, a rational taxation scheme, and a bureaucracy to collect those taxes.What were the "positive" qualities of Charles? He seemed to just piss off all his neighbors.
In fact he was not the only noble personage to go down this road: Matthias Corvinus of Hungary also created a standing army during the 15th century (the so-called "Black Army"). Like Charles he raised unpopular taxes unpopular to pay for it. But Matthias ended up with an army that could conquer big chunks of Bohemia, while Charles' army got slapped around. I'm trying to figure out how Matthias succeeded while Charles utterly failed.