I've got one of those Eden 501's and after a few hours of rocking and shaking to get all the air out, it ran really quiet.
However it was downstairs, not in my bedroom !
They are a great filter option for small tanks, but I think there is bit of a design flaw in them. Nothing too serious and with a little bit of tweaking it can easily be overcome.
When you open the filter you'll see that the Outflow pipe to the tank attches to the section with the internal sponge filter. The Intake pipe brings water from the tank direct to the bacterial ceramic media.
This pic helps show what I mean:
I think it's down to the fact that this filter is basically a modified sponge filter that was for internal use. They've taken the pump and added it to an external box.
Ideally you'd want any rubbish straining off before it gets that far, not just before it is returned to the tank. I have noticed that in it's default state, the ceramic media gets clogged up quite quickly and water flow can start to reduce.
I tried two methods to overcome this, both very simple and both seemed to work.
First I tried simply swapping the sponge and cermaic media between compartments. You just need to be careful positioning the pipe from the bottom of the pump down in to the ceramic. It worked, but was a bit fiddly when
cleaning the filter. Everytime you open the filter it was hard to get the pipe back into the ceramic, without distrubing everything.
A far simpler option is to leave a small gap and place some sponge ontop of the cermaic media. This filters out most of the junk from the tank and leaves things underneath much cleaner. I also swapped out some of the original sponge for a much finer grade and this worked very well.
Al