It is as good as advertised. AS good as any top brand Flux gel. Good heat transfer. Thick. Leaves little residue. Sure if you do LR application it will make a mess you will need to clean. But you clean flux anyways right? Have not tested leaving it on the non thinned trace or pad for longer time so I am not sure is it aggressive if left on the board.
On the other side plunger is waste of time. It will not click into the syringe and will fall out. Can't back off either. Biggest green needle is questionable at least. Can't push out a millimeter out of the syringe with suggested needle and plunger combo. Waste of the time :(