P.M.
Our Dyson has such powerful suction that it's hard to use the hand attachments - the amount of strength needed to move it over surfaces is awfully hard on my joints. Other than that and the noise, I like the machine. It does a very clean job and exhausts little or no dust back into the air.
I wonder if you've checked to see if anything is clogging the hose or if the hose has any breaks in it, and if it's set at the correct height for the surface you are vacuuming. If it's really just not working well, I am told that the Dyson company is very good about helping customers work through technical and warranty problems. Good luck.