Eh, I can't hear you, I have my top hat heater (basically identical to the image you posted) on...
Very loud (IMHO), the 'rush' of the burning gas is more than one might expect. Imagine a 1000 blow torches all on at the same time!
Good side: dang things put out a lot of heat!
Bad side: They stink big time, and **** the oxygen from the building.
Good side: never ever measured any CO from mine.
Bad side: the stink is so bad that I am replacing it with a proper heater (150 K BTU one.)
For the price that heater can't be beat, but it does have some major down sides. I doubt it will be less noisy than your torpedo heater.