That hoover windtunnel was rated number 1 in the most recent Consumer reports review (march 2012).
That said, they did not review the Dyson DC40 or DC41 (or any of the current gen dysons as far as I can tell)
They reviewed the bagless DC41 and it came in like 24th.. They said the DC28 was much better. I'm not sure how that can be.. Maybe this link will work: