Results of my non-scientific test:
Viniger and baking soda -- I'm sure it's good for something, but not removing leaf stains. Cost around $0 at any grocery store.
FSR -- worked the best of the three, and pretty simple to use. Cost around $10 at West Marine.
Spray Nine Patio Furniture Cleaner -- Came in the middle of the pack. Left some stains that FSR removed. Cost around $5 at Ace Hardware.
Please Note: I did not try Spray Nine marine cleaner, because my local hardware store did not have it, and did not try Y-10 or Krazy Kleen because I'd already bought the others and the grant from the National Science Foundation is yet to arrive. If someday I try them, You'll hear it first here.