The benefit of taking philosophy courses

I have never set foot inside a college classroom to study philosophy (technology, business, and jazz piano were my subjects).  Over the last year my free moments have mostly gone towards studying philosophy.  (A 'free moment' is the hour before work when my wife is still tucked into bed.)  My understanding of the subject seems to be moving along nicely, but my belief is that studying philosophy in the academy admits of some considerable benefits.

1. Guidance while wading through obscure passages and authors.  For instance: elusive German philosophers whose names begin with 'H' (Husserl, Heidegger, and Hegel).
2. Feedback on writing skills, weak points, and general grasp of the topic at hand.
3. Question/answer with the professor.
4. Generally you would expect the professor to give an overview of relevant themes, historical contexts, trends, important versus non-important aspect, etc.

Now an objection: given the wealth of materials available to any earnest student, surely classroom learning is commensurate with solitary study.  Of course, the ceteris paribus here is the effort put forth by the student to master the subject.  But commensurate with respect to what?  An isolated student can achieve the same quality education as the collegiate student, but probably not in the same amount of time.  You pay to progress at a more efficient rate.  And that might persuade someone to pay tuition.  It has even tempted me a few times.

But this only applies to undergraduate courses.  I have no idea what the average grad course in philosophy is like.  But this I do know: my chances are slim for acceptance into an upper level philosophy program without an undergrad degree.