The only parts of the metric system that most of us Cannuks have still not quite got the hang of are hectors and kilopascals.
I have to admit to a certain dislike for metric 'units' that are simple mixtures of the basic units, but get new names. Isn't N/m^2 good enough? What's the point of having your basic units be related, if you go and give combination context-less new names? (not terribly fond of Newtons, either!)
And hectares (?)?? When "ares" have gone away, and it's just some large number of m^2 anyway? The way I was taught, scientific notation goes hand-in-glove with metric, and what's the point in making up a new name just because your number gets big (or small.) (not fond of micron or angstrom either.)