Product review (4 stars): Excellent product
Have used for the months now the stainless steel version. It replaced an older Jen-air 30" downdraft when we replaced our countertops to engineered quartz slab.  The fan exhaust fits right into the previous exhaust outlet without any modifications.  The stainless edges goes well with our other appliances that are stainless.  I thought moving from coils to glass ceramic would present problems with heating times - I'm amazed how quickly this heats up and how the heat stays localized under the pot/pan.  This heats up just slightly slower than my previous coiled model - that's about the only con.  It still conducts heat so well, that water droplets levitate on the surface when it's on hi setting from the steam.

The pro's are that it's beautiful, easy to clean, won't scratch my copper pans, has a very well designed retractable fan switch.  A word on the cleaning - it does require you to wipe it after spills or the material begins to bake on and become harder to remove.  However, as we wipe our countertops nearby, we wipe the glass surface and this keeps it clean.  I've used a simple retractable razor blade once or twice to remove any blackened deposits that sometimes accumulate like the manual says.  And before we have guests, I use Cerama-bright to make it sparkle.

As far as durability, as with any ceramic cooking surface, go easy on it with the physical abuse.  I used to slam the pans/pots on the previous coiled cooktop to get better conduction and to agitate the cooking; if you do this the same on glass ceramic, I'm sure it will chip or crack.  Instead, the surface is flat and conducts well to similarly flat bottomed pans and pots. A simple sliding motion is all that's needed to agitate the food when cooking.  If by habit you still want to abuse the surface (and your pots/pans) and/or be lazy and not clean up (even your nearby countertops), my advice is to stay with coils or use gas.

I saw the negative reviews elsewhere and am suspicious since so many are worded similarly.

Edit:  We did get a scratch on it from a guest using a heavy iron skillet that wasn't so flat on the bottom.  I have since discovered usage of  a heavy, thick copper diffuser plate than can be used to protect the surface on occasion where a heavy pan/pot is needed.