In his teens he was and he was send of to england to a boarding school.
He studied history in Leiden. His final essay was about General de Gaulle and France's decission to get out of NATO in 1953 (or something like that). He is not as bright as his brother Johan-Friso for example (who did 2 difficult studies, but he has another gift, he seems to be able to 'connect' to people, which is even more important in his future role.
The idea that he is not that bright was started when in the 80-ties the court stopped publishing his schoolgrades (I would hate my grades to be published as well) and later because he seemed to enjoy studentlife in leiden a bit to much.
Today he seems very much dedicated to his causes and prepared for the job. He seems down-to-earth, which is considered a big asset in The Netherlands. People expect him to have a more relaxed attitude than his mother and that he will reign more in the style of his grandmother. I have my doubts about that, I think he and Maxima will be (/are!) as worried as Beatrix about privacy etc, and not as open as Juliana was with her family for example.