Product review (4 stars): Cooktop is nice - the exhaust unit is not
My stove top arrived quickly and was well packed.  It was replacing an earlier model (about 15 years old) of the same brand.  It does heat quickly (about the same as our olderunit)and I like the improvements they made to make the surface area flat around the control knobs.  In short, compared to our older model, there are much fewer places for dirt to collect.  Our old model also had steel borders around the cooking models, and these wore out over time and looked ugly.  This new model gets rid of the borders, which is also a nice improvement.

So I would give it 5 stars, except that there are issues with the down draft.  First, the fan unit and exhaust hole protrude much futher down than the previous model.  This gives 2-3 inches of less room to work with, which makes a HUGE difference.  BY the time you put on the rectangle-to-round adapter, you are basically hitting the bottom of the cabinet.  It was impossible  to connect to the existing vent piping, which is very annoying since the old unit was basically the same model, etc.. as this new one.  The only way I was able to get everything to work was to go to a smaller pipe size (down from 6" to 5") and run the 5" pipe a few inches into the existing 6 inch pipe, and wrap it up with ducting tape.  In the end it worked, but I feel it is a design flaw to have the exhaust protrude so far down,which really limits your options if replacing an existing stove top.  When installed in a standard countertop, you can expect to have less than 2" of room between the end of the exhaust adapter, and the bottom of the cabinet.

It also does not come with any clamps to hold it in place (the old unit had long screws for this).  However I justkeep it in place by gravity,and this seems to work fine.