Product review (4 stars): Good vent hood, poor duct (but how to fix)
The plastic part of the vent hood is sturdier than the one replaced.  On the old vent the flaps were thinner and had actually eroded away due to the sun breaking them down, the flaps on this vent were heavier and there were 2 instead of 3.  However, one should be careful when installing this vent as the short piece of duct on the back of the vent is thin, almost paper thin, and will come apart when other duct is inserted into it.  What I ended up doing to address this was: 1) put a piece of aluminum tape over the duct seam to prevent it from coming apart when the other duct is inserted, and 2) put a small 'dent' in the end of other duct at the same point where the seam is on the vent duct to avoid pressing on the vent duct seam.  Also make sure that the seam on the vent duct does NOT line up with the seam on the other duct as that will push the vent duct apart too.  Otherwise would have been 5 stars.