Leutstärke: Both do is nothing, and identical to my feeling. However, the blue vacuum cleaner (Rowenta RO5911) has a controller, so you can also suck almost silently. However then be left to the Saugstärge wishes.
After my Dyson are, both, however, a treat for the ears, as it the volume is almost torture when Dyson already.
Weight: terms of weight, are both I think equal weight within 6-7 kg, with the blue (RO5911) is a little awkward, since it was built more in the length. In addition, the blue turns worse than how the yellow (Rowenta RO8324EA).
All in all I am satisfied with the yellow, so I have the blue zurückgeschikct. Both have their pros and cons,
where for me the better quality has given the Ausshlag.
PS: Both vacuums are designed more for hard floors. When times comes a minor rug that's ok, but if you have a lot of carpet, then you should look for another vacuum cleaner, because when sucking both rattling over the carpet.