Summary: For some reason GE decided to make the bottom of the backdraft rectangular instead of circular, which is how the vents are made. this required an extensive amount of work to get the backdraft vent hook upped. The cook top itself works fine. The fan, when on low, is pretty quiet and does the job well.
Summary: I initially liked this appliance, however, the more I use it, the less I like it. It's made of cheap material (China) and doesn't hold up well. The knobs are plastic overlaid with chrome and will melt if on high heat or accidentally touched with a pan. Had I realized GE was now made in China, I would have never bought the item. GE is just another China company producing cheap products.
Summary: Just installed today. I would NOT buy it again. The downdraft sucks away the heat so that the food being cooked takes forever to cook. A small 1/2 quart pot of soup was still lukewarm after five minutes on high heat with the downdraft turned on. I finally had to turn off the downdraft to get it to come to a boil. And the downdraft only works well on the two back burners.
Summary: All downdraft cook tops are, according to their manufacturers, submarginal at removing odors, heat and what you would expect a vent to vent. My mistake twice, first with an electric cook top and then with a gas downdraft. Too late now, the cook top is mounted in a island with no provision for a vent. Big mistake. Also note the price for this cook top does not include the other two burners for the left side. Nor does it include the grill attachment.
Summary: I had this cooktop for 7 years at a home I just sold. It is a beautiful cooktop and it is a very solid unit. We never had any problems with it. Yes, like other reviewers have mentioned it does need to be cleaned on a regular basis. You can't get grease on the cooktop and continue to splatter more and more grease on it without wiping it off or it will build up. But if this does happen like it did on mine it can easily be restored to look new again.