Truth be told, I came to Schopenhauer's work reluctantly, having been put off by Nietzsche, who - despite an early infatuation with Schopenhauer - later turned against his "mentor" (of sorts) claiming his work lacked any ethical applicability.
Yet, as an avid reader of Buddhist and Western philosophical texts, I found myself repeatedly drawn towards Schopenhauer through various resources. So after putting my prejudices aside, I went to the text itself, and I have to say, I consumed this volume with great enthusiasm: I find Schopenhauer to be one of the clearest, most articulate philosophers in the Western tradition (not unlike a Zen master). His work is, in a word, genius.
OK, sure, the "Buddha of Frankfurt" (his nickname) was no saint, but then again, who is? If you ask me, Schopenhauer's thinking is not to be "followed" as such, but rather, "understood," as I find his quiet reserve inspirational and his attempts at personal fulfillment through ART to be wise and sagely advice.
Personally, I found that The World as Will and Idea reminded me of Richard Dawkins' The Selfish Gene. We are, it seems, reproduction machines. (I also think the fledgling terms Id and Ego might be brought into play as well.)
Finally, I must concur with Schopenhauer's university philosophy professor, G.E. Schulze, who told the young thinker to stick with ONLY Plato and Kant. But to that small list I would now add one more name: Arthur Schopenhauer, as he brilliantly merges the thought of Plato and Kant to form a truly original philosophy - and he does so in a much clearer way than, say, Hegel or any other German Idealist might have. That said, I think it is helpful to have read some Plato and Kant before dipping into this text, as I found - and perhaps this is a petty gripe, I dunno - that the introduction by Dave Berman was, unlike Schopenhauer's fine prose itself, dull, unhelpful and, ultimately, uninspiring.
I highly recommend this text for both beginners and experts in the field -it is THAT good...and it just might change your whole perspective, if not your way of life. Amazing!