I was puzzled at the different reactions of other reviewers, and when I first used this I too could not get anything other than a spray pattern when turning the rear dial - no jet.
However, I discovered by accident that you also need to turn the spray head itself - it twists several turns and this has to be used in conjunction with the rear dial. Now I can get all sorts of sprays and jets.
A simple 'instruction' sheet would have been all that was needed to clarify this. It's quite ridiculous to have markings on the rear dial suggesting that is the main control with no mention that there is another adjustment. No wonder some have been disappointed. At the time of writing, Amazon currently have this product 'under review', and probably why it is being given away free with purchase of a hoze. But it does do everything it claims.
Mine also leaks occasionally from the handle - but not in normal use. I have yet to determine what exactly causes this momentary phenomenon!
My advice: get it if you want a spray gun. It does work