I don't think I've unequipped this since I got it, it's just so satisfying to charge up with a flare gun, then sneak up behind the action and obliterate the entire enemy team
People get so much more upset about it than combo Pyros for some reason despite it being infinitely easier to kill a Phlog Pyro
If they're not powered up they're hardly a threat and can be dispatched with relative ease even if they ambush you because direct flamethrower damage is agonizingly slow, and if they fill their bar then 100%+ speed classes can run away, Soldiers and Demomen can knock them back and/or explosive jump away, and Heavies can single-handedly kill them if they focus their fire during the taunt animation
People never seem to remember that you can just retreat for a few seconds and completely defuse the situation, they always backpedal and attempt to kill you while you run at them (which does work a lot of the time but still)