Originally Posted by Mando Knight
Backburner crits are the highest sustained DPS a Pyro can get, but the Degreaser/Axetinguisher combo will finish off most single opponents almost immediately, so the difference mostly comes in when you have multiple enemies' backs to your nozzle.
Oh yeah, I just sort of discount backburner because I rely on airblast way too much to have the increased cost in my setup.
I suppose that one relies on how you play the pyro, but I'd still call both a straight upgrade to the flamethrower. Just depends on your playstyle as to which you use.