Haven't been there myself; didn't want to spend the money but I have heard a whole range of reactions to it: some said it was the best few days of their lives; some said it wasn't worth it for how expensive the whole scene is; other said it was worth the expense for a once in a lifetime couple of days there....
So how much you like to party is the main consideration I guess....
I guess I should add that I don't regret not going. Believe me, you can party pretty much anywhere in Europe and definitely in mainland Spain.