If you playing solo versus the a swarm of pyros without much strategy but with lots of firepower, a lvl 3 sentry is the only thing I found which really give them a pause.

I though the Dragon flamethrower would be weak but the rate of fire is fast and the requeriment of being on fire isn't relevant right now. Maybe it will be weaker when the Pyro craze cooldown but right now they do the job.

I wonder what Valve will do to the heavy (my favorite class) but I'll not hold my breath on it given how long it took for this update to come.