Oh sure, he's a correlationist. But what a beautiful writer. And his arguments, when you expand them in the OOO way (just universalizing the gap between phenomenon and thing) it's very very good indeed.
As a Buddhist I'm here to say that actually his argument is a very beautiful and truly Buddhist application of Kant. Very interesting that you can get there from Kant.
I kept on reading him after class a couple of weeks ago. It's funny how in the introduction to The World as Will and Representation Schopenhauer specifies that you won't understand his stuff the first time you read it, so you should read it twice. It's quite evident in my case.