I agree its a difficult choice. On the other hand they do say practice makes perfect. It all depends on whether you are practicing the wrong things.... I'm not dissing the course I just think I would rather do 3 or 4 track days for the same money.
I read the books, videod what I was doing and self taught on trackdays tbh so in the same boat; couldn justify £800 as it was then n 2 levels when I felt I cold learn 90% of it myslef with some mates help on track observing. Dunno of I did but better than I was