It's very quiet, I'd say just slightly above the noise level of the main machine I use at home (a Sullivan R6 or something like that). My biggest complaint with the Puritan is that the On/Off is hard to find in the dark -- it's just about flush with the box (not raised, as on other systems).

The hose does take up space, but its flexibility at least gives you a few more packing options than the monolithic main unit.