Product review (1 stars): Does not work well with propane
In the past I have had several houses in towns where natural gas was available, and I came to appreciate the quick response of gas flame for cooking.  Now in a rural area with only propane service, I thought that it would be a good idea to replace the electric cooktop with gas.  I bought this cooktop but am totally dissatisfied, and will re-install the electric.
LP requires different conditions for combustion than does NG.  NG cooktops run on a pressure of 4 inches water column, whereas LP needs 10 inches water column.  For equivalent burner BTU capacity, the LP orifices at the burners must be about 3x smaller in area (1.7x smaller in diameter) than the corresponding NG burner orifices.  So the cooktop is sold with a set of substitute orifices and a pressure regulator that can be reconfigured from 4 to 10 inches.
The problem is this: flow through the burner orifice is controlled by a variable orifice in series with the burner orifice (i.e., a rotary valve leading to the knob).  This variable orifice is sized for good NG performance.  When used with LP orifices, two problems are immediately apparent: (1) the burner flame is HIGH for about 3/4 of knob rotation, and (2) the flame cannot be turned down far enough to simmer a typical pan on any burner except the small one (even though a "low flame" adjustment is available).
I believe that the only solution is to buy a high end cooktop like Dacor or SubZero, for which there is a dedicated LP model with properly sized variable orifices.  GE seems to have the high end price without the high end performance.
Most of the common appliance brands use the burner orifice substitution scheme, so I assume that they have a similar problem.
GE's customer service folks are finished talking to you once they learn that you have propane.  They tell you to go to your propane supplier or your local plumber for help.  I am sure that GE engineers understand this problem.  It must be that the marketing department feels no need to service the relatively small number of propane customers.